Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

We describe the FundamentalNeutronPhysics Beamline (FnPB) facility located at the Spallation Neutron Source at Oak Ridge National Laboratory. The FnPB was designed for the conduct of experiments that investigate scientific issues in nuclear physics, particle physics, astrophysics and cosmology using a pulsed slow neutron beam. We present a detailed description of the design philosophy, beamline components, and measured fluxes of the polychromatic and monochromatic beams.

Fundamentals of Plasma Physics James D. Callen University of Wisconsin, Madison June 28, 2006 #12;PREFACE Plasma physics is a relatively new branch of physics that became a mature science over the last half of the 20th century. It builds on the fundamental areas of classical physics: mechanics

An introduction to the methodology of neutron reflectometry is given in which the fundamental aspects regarding the actual performance of specular reflection measurements and subsequent analysis of the data are described. The application of this technique to the determination of interfacial structure or composition in thin film and multilayer materials of interest in the fields of magnetism, superconductivity, polymer science, electrochemistry, and biology is illustrated by specific examples. The microscopic information provided by neutron reflectivity which complements that obtained by other probes is emphasized, in particular information which is obtainable because of the inherent isotopic (most notably in the case of hydrogenous materials) or magnetic moment (both magnitude and orientation) sensitivity of the neutron.

The Satellite Test of the Equivalence Principle (STEP) will advance experimental limits on violations of Einstein's Equivalence Principle from their present sensitivity of 2 parts in $10^{13}$ to 1 part in $10^{18}$ through multiple comparison of the motions of four pairs of test masses of different compositions in a drag-free earth-orbiting satellite. We describe the experiment, its current status, and its potential implications for fundamentalphysics. Equivalence is at the heart of general relativity, our governing theory of gravity, and violations are expected in most attempts to unify this theory with the other fundamental interactions of physics, as well as in many theoretical explanations for the phenomenon of dark energy in cosmology. Detection of such a violation would be equivalent to the discovery of a new force of nature. A null result would be almost as profound, pushing upper limits on any coupling between standard-model fields and the new light degrees of freedom generically predicted by these theories down to unnaturally small levels.

The Satellite Test of the Equivalence Principle (STEP) will advance experimental limits on violations of Einstein's Equivalence Principle from their present sensitivity of 2 parts in $10^{13}$ to 1 part in $10^{18}$ through multiple comparison of the motions of four pairs of test masses of different compositions in a drag-free earth-orbiting satellite. We describe the experiment, its current status, and its potential implications for fundamentalphysics. Equivalence is at the heart of general relativity, our governing theory of gravity, and violations are expected in most attempts to unify this theory with the other fundamental interactions of physics, as well as in many theoretical explanations for the phenomenon of dark energy in cosmology. Detection of such a violation would be equivalent to the discovery of a new force of nature. A null result would be almost as profound, pushing upper limits on any coupling between standard-model fields and the new light degrees of freedom generically predicted by these ...

The Satellite Test of the Equivalence Principle (STEP) will advance experimental limits on violations of Einstein's equivalence principle from their present sensitivity of two parts in 1013 to one part in 1018 through multiple comparison of the motions of four pairs of test masses of different compositions in a drag-free earth-orbiting satellite. We describe the experiment, its current status and its potential implications for fundamentalphysics. Equivalence is at the heart of general relativity, our governing theory of gravity and violations are expected in most attempts to unify this theory with the other fundamental interactions of physics, as well as in many theoretical explanations for the phenomenon of dark energy in cosmology. Detection of such a violation would be equivalent to the discovery of a new force of nature. A null result would be almost as profound, pushing upper limits on any coupling between standard-model fields and the new light degrees of freedom generically predicted by these theories down to unnaturally small levels.

Ongoing fascination with quantum mechanics keeps driving the development of the wide field of quantum-optics, including its neutron-optics branch. Application of neutron-optical methods and, especially, neutron interferometry and polarimetry has a long-standing tradition for experimental investigations of fundamental quantum phenomena. We give an overview of related experimental efforts made in recent years.

Physics 122 Â­ Fundamentals of Physics II Syllabus for Fall 2012 Course description The second of a two-semester series in general physics. The course is a continuation of PHYS 121, and covers waves, electricity and magnetism, optics, and modern physics. This survey course, together with PHYS 121, generally

Astrophysical observations provide robust evidence that our current picture of fundamentalphysics is incomplete. The discovery in 1998 that the expansion of the Universe is accelerating (apparently due to gravitational repulsion between regions of empty space!) presents us with a profound challenge, at the interface between gravity and quantum mechanics. This "Dark Energy" problem is arguably the most pressing open question in modern fundamentalphysics. The first talk will describe why the Dark Energy problem constitutes a crisis, with wide-reaching ramifications. One consequence is that we should probe our understanding of gravity at all accessible scales, and the second talk will present experiments and observations that are exploring this issue.

, open problems and future perspectives in connection with dark energy and string theory are overviewed. Contents I. The history of the universe 1 II. FundamentalPhysics 2 III. Essentials of Cosmology 3 IV and Outlook 13 References 14 I. THE HISTORY OF THE UNIVERSE The history of the universe is a history

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.

Understanding the equation of state (EOS) of cold nuclear matter, namely, the relation between the pressure and energy density, is a central goal of nuclear physics that cuts across a variety of disciplines. Indeed, the limits of nuclear existence, the collision of heavy ions, the structure of neutron stars, and the dynamics of core-collapse supernova, all depend critically on the equation of state of hadronic matter. In this contribution I will concentrate on the special role that nuclear physics plays in constraining the EOS of cold baryonic matter and its impact on the properties of neutron stars.

We explore the unique and fascinating structure of neutron stars. Although neutron stars are of interest in many areas of Physics, our aim is to provide an intellectual bridge between Nuclear Physics and Astrophysics. We argue against the naive perception of a neutron star as a uniform assembly of neutrons packed to enormous densities. Rather, by focusing on the many exotic phases that are speculated to exist in a neutron star, we show how the reality is different and far more interesting.

The purpose of this guide is to provide a consistent, standardized approach to performing neutronics/physics analysis for experiments inserted into the Advanced Test Reactor (ATR). This document provides neutronics/physics analysis guidance to support experiment design and analysis needs for experiments irradiated in the ATR. This guide addresses neutronics/physics analysis in support of experiment design, experiment safety, and experiment program objectives and goals. The intent of this guide is to provide a standardized approach for performing typical neutronics/physics analyses. Deviation from this guide is allowed provided that neutronics/physics analysis details are properly documented in an analysis report.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

...Discussion Meeting Issue The fundamental constants of physics, precision...calls to mind an axiom of the fundamental constants field, namely...uncertainties.) Although it does not ensure that an unsuspected...uncertainty of interest in the fundamental constants field at that time...

PHYSICSPhysics is the fundamental science: the study of matter and energy and of their interactions. Physics is the basis for all science and for all applied science and engineering. Physicists study everything from elementary particles to galaxies, from semiconductors to chaos. Because physics

Last year, about 100 fundamentalphysics researchers met twice to develop plans for the future in this research area. The results of these meetings have been documented in a presentation package titled A Road...

The chart produced by the Fundamental Particles and Interactions Chart Committee is explained. This chart describes the properties of elementary particles according to the Standard Model and is intended for physics instruction at the high school and undergraduate levels. (AIP)

A web of interlocking observations has established that the expansion of the Universe is speeding up and not slowing, revealing the presence of some form of repulsive gravity. Within the context of general relativity the cause of cosmic acceleration is a highly elastic (p\\sim -rho), very smooth form of energy called ``dark energy'' accounting for about 75% of the Universe. The ``simplest'' explanation for dark energy is the zero-point energy density associated with the quantum vacuum; however, all estimates for its value are many orders-of-magnitude too large. Other ideas for dark energy include a very light scalar field or a tangled network of topological defects. An alternate explanation invokes gravitational physics beyond general relativity. Observations and experiments underway and more precise cosmological measurements and laboratory experiments planned for the next decade will test whether or not dark energy is the quantum energy of the vacuum or something more exotic, and whether or not general relativity can self consistently explain cosmic acceleration. Dark energy is the most conspicuous example of physics beyond the standard model and perhaps the most profound mystery in all of science.

X-ray free electron lasers (FELs) have been proposed to be constructed both at SLAC in the form of the so-called Linac Coherent Light Source as well as at DESY, where the so-called XFEL laboratory is part of the design of the electron-positron linear collider TESLA. In addition to the immediate applications in condensed matter physics, chemistry, material science, and structural biology, X-ray FELs may be employed also to study some physics issues of fundamental nature. In this context, one may mention the boiling of the vacuum (Schwinger pair creation in an external field), horizon physics (Unruh effect), and axion production. We review these X-ray FEL opportunities of fundamentalphysics and discuss the necessary technological improvements in order to achieve these goals.

We consider the astrophysical reaction rates for radiative neutron capture reactions (n,?) in the crust of a neutron star. The presence of degenerate neutrons at high densities (mainly in the inner crust) can drastically affect the reaction rates. Standard rates assuming a Maxwell-Boltzmann distribution for neutrons can underestimate the rates by several orders of magnitude. We derive simple analytical expressions for reaction rates at a variety of conditions with account for neutron degeneracy. We also discuss the plasma effects on the outgoing radiative transition channel in neutron radiative capture reactions and show that these effects can also increase the reaction rates by a few orders of magnitude. In addition, using detailed balance, we analyze the effects of neutron degeneracy and plasma physics on reverse (?,n) photodisintegration. We discuss the dependence of the reaction rates on temperature and neutron chemical potential and outline the efficiency of these reactions in the neutron star crust.

Three aspects of the research project Surface physics with cold and ultracold neutron reflectometry'' were stressed during the present first year: (1) Setup of the reflectometer facility at the research reactor of the Rhode Island Nuclear Science Center. The installation provides a narrow pencil beam'' analyzed by time of flight using a chopper system. Following beam characterization and a test measurement of the total cross section of copper single crystal first reflectivity measurements are currently performed using a supermirror. (2) Design stud for the ultracold neutron imaging system, with involvement of the relevant industry. Bids are available for several components indicating that it will be very difficult to build the entire system unless further funds become available. (3) Analysis of features of neutron reflection from surfaces with special emphasis on the effect of surface roughness both on the specular beam and the diffusely reflected and refracted intensity. Previous theoretical studies were supplemented by further numerical calculations of diffuse scattering distributions using different models. Application of ultracold and cold neutron reflectometry to the study of liquid-vapor phase transition were discussed. The theoretical work also includes the development of tentative ideas for novel fundamentalphysics experiments.

We study the $f$-mode frequencies and damping times of nonrotating neutron stars (NS) in general relativity (GR) by solving the linearized perturbation equations, with the aim to establish "universal" relations that depend only weakly on the equations of state (EOS). Using a more comprehensive set of EOSs, we re-examine some proposed linearizations that describe the $f$-mode parameters in terms of mass and radius of the neutron star (NS), and we test a more recent proposal for expressing the $f$-mode parameters as quadratic functions of the effective compactness. Our extensive results for each equation of state considered allow us to study the accuracy of each proposal. In particular, we find that the damping time deviates quite considerably from the proposed linearization. We introduce a new universal relation for the product of the $f$-mode frequency and damping time as a function of the (ordinary) compactness, which proved to be more accurate. The relations using the effective compactness on the other hand...

Possible violations of fundamentalphysical principles, e.g. the Einstein Equivalence Principle on which all metric theories of gravity are based, including General Relativity, would lead to a rotation of the plane of polarization for linearly polarized radiation traveling over cosmological distances, the so-called cosmic polarization rotation (CPR). We review here the astrophysical tests which have been carried out so far to check if CPR exists. These are using the radio and UV polarization of radio galaxies and the polarization of the cosmic microwave background (both E-mode and B-mode). These tests so far have been negative, leading to upper limits of the order of one degree on any CPR angle, thereby increasing our confidence in those physical principles, including General Relativity. We also discuss future prospects in detecting CPR or improving the constraints on it.

Gamma-ray Astronomy studies cosmic accelerators through their electromagnetic radiation in the energy range between ~100 MeV and ~100 TeV. The present most sensitive observations in this energy band are performed, from space, by the Large Area Telescope onboard the Fermi satellite and, from Earth, by the Imaging Air Cherenkov Telescopes MAGIC, H.E.S.S. and VERITAS. These instruments have revolutionized the field of Gamma-ray Astronomy, discovering different populations of gamma-ray emitters and studying in detail the non-thermal astrophysical processes producing this high-energy radiation. The scientific objectives of these observatories include also questions of fundamentalphysics. With gamma-ray instruments we study the origin of Galactic cosmic rays, testing the hypothesis or whether they are mainly produced in supernova explosions. Also, we obtain the most sensitive measurement of the cosmic electron-positron spectrum between 20 GeV and 5 TeV. By observing the gamma-ray emission from sources at cosmological distances, we learn about the intensity and evolution of the extragalactic background light, and perform tests of Lorentz Invariance. Moreover, we can search for dark matter by looking for gamma-ray signals produced by its annihilation or decay in over-density sites. In this paper, we review the most recent results produced with the current generation of gamma-ray instruments in these fields of research.

An Autonomous, Emergent Model of FundamentalPhysics: Understanding the Universe by Designing. We seek to build an autonomous model that produces known physics in a completely self/16/2005. #12;2 An Autonomous, Emergent Model of FundamentalPhysics Contents Introduction 3 Autonomous Models

...isotopic symmetry of the nuclear force is an...magnetics and pions in nuclear physics...symmetry of the Minkowski vacuum under changes of the...scale of atomic and nuclear physics is so much...generation of particle acceleratorsa discovery of new...

...but the production rate, at least in the...problems in modern physics that remain to be...of equal production rates. In fact, the charge...simply by letting them pass through a foil, called...potential that made them pass easily (and at high...to understand. The rate determining factor...

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

With the University of Idaho, Ohio State University and Clarksean Associates, this research program has the long-term goal to develop reliable predictive techniques for the energy, mass and momentum transfer plus chemical reactions in drying / passivation (surface oxidation) operations in the transfer and storage of spent nuclear fuel (SNF) from wet to dry storage. Such techniques are needed to assist in design of future transfer and storage systems, prediction of the performance of existing and proposed systems and safety (re)evaluation of systems as necessary at later dates. Many fuel element geometries and configurations are accommodated in the storage of spent nuclear fuel. Consequently, there is no one generic fuel element / assembly, storage basket or canister and, therefore, no single generic fuel storage configuration. One can, however, identify generic flow phenomena or processes which may be present during drying or passivation in SNF canisters. The objective of the INEEL tasks was to obtain fundamental measurements of these flow processes in appropriate parameter ranges.

The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ('PREX') at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in {sup 208}Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron beams may impact the physics of neutron stars.

Using modern methods of reactor physics we have performed full-scale calculations of the natural reactor Oklo. For reliability we have used recent version of two Monte Carlo codes: Russian code MCU REA and world wide known code MCNP (USA). Both codes produce similar results. We have constructed a computer model of the reactor Oklo zone RZ2 which takes into account all details of design and composition. The calculations were performed for three fresh cores with different uranium contents. Multiplication factors, reactivities and neutron fluxes were calculated. We have estimated also the temperature and void effects for the fresh core. As would be expected, we have found for the fresh core a significant difference between reactor and Maxwell spectra, which was used before for averaging cross sections in the Oklo reactor. The averaged cross section of Sm-149 and its dependence on the shift of resonance position (due to variation of fundamental constants) are significantly different from previous results. Contrary to results of some previous papers we find no evidence for the change of the fine structure constant in the past and obtain new, most accurate limits on its variation with time: -4 10^{-17}year^{-1} < d alpha/dt/alpha < 3 10^{-17} year^{-1} A further improvement in the accuracy of the limits can be achieved by taking account of the core burnup. These calculations are in progress.

Three aspects of the research project ``Surface physics with cold and ultracold neutron reflectometry`` were stressed during the present first year: (1) Setup of the reflectometer facility at the research reactor of the Rhode Island Nuclear Science Center. The installation provides a narrow ``pencil beam`` analyzed by time of flight using a chopper system. Following beam characterization and a test measurement of the total cross section of copper single crystal first reflectivity measurements are currently performed using a supermirror. (2) Design stud for the ultracold neutron imaging system, with involvement of the relevant industry. Bids are available for several components indicating that it will be very difficult to build the entire system unless further funds become available. (3) Analysis of features of neutron reflection from surfaces with special emphasis on the effect of surface roughness both on the specular beam and the diffusely reflected and refracted intensity. Previous theoretical studies were supplemented by further numerical calculations of diffuse scattering distributions using different models. Application of ultracold and cold neutron reflectometry to the study of liquid-vapor phase transition were discussed. The theoretical work also includes the development of tentative ideas for novel fundamentalphysics experiments.

0-92 0-92 JUNE 1992 DOE FUNDAMENTALS HANDBOOK CLASSICAL PHYSICS U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P. O. Box 62, Oak Ridge, TN 37831; (615) 576-8401. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE92019784 CLASSICAL PHYSICS Rev. 0 CP ABSTRACT The Classical PhysicsFundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the

Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of a neutron source facility. It is based on the use of an electron accelerator driven subcritical (ADS) facility with low enriched uranium fuel, using the existing electron accelerators at KIPT of Ukraine [1]. The neutron source of the subcritical assembly is generated from the interaction of 100-KW electron beam, which has a uniform spatial distribution and the electron energy in the range of 100 to 200 MeV, with a natural uranium target [2]. The main functions of the facility are the production of medical isotopes and the support of the Ukraine nuclear power industry. Neutron beam experiments and material studies are also included. Over the past two-three decades, structures with characteristic lengths of 100 {angstrom} and correspondingly smaller vibrational energies have become increasingly important for both science and technology [3]. The characteristic dimensions of the microstructures can be well matched by neutrons with longer vibrational wavelength and lower energy. In the accelerator-driven subcritical facility, most of the neutrons are generated from fission reactions with energy in the MeV range. They are slowed down to the meV energy range through scattering reactions in the moderator and reflector materials. However, the fraction of neutrons with energies less than 5 meV in a normal moderator spectrum is very low because of up-scattering caused by the thermal motion of moderator or reflector molecules. In order to obtain neutrons with energy less than 5 meV, cryogenically cooled moderators 'cold neutron sources' should be used to slow down the neutrons. These cold moderators shift the neutron energy spectrum down because the thermal motion of moderator molecules as well as the up-scattering is very small, which provides large gains in intensity of low energy neutrons, E < 5 meV. The accelerator driven subcritical facility is designed with a provision to add a cryogenically cooled moderator system. This cold neutron source could provide the neutrons beams with lower energy, which could be utilized in scattering experiment and material structures analysis. This study describes the performed physics analyses to define and characterize the cold neutron source of the KIPT neutron source facility. The cold neutron source is designed to optimize the cold neutron brightness to the experimental instruments outside the radial heavy concrete shield of the facility. Liquid hydrogen or solid methane with 20 K temperature is used as a cold moderator. Monte Carlo computer code MCNPX [4], with ENDF/B-VI nuclear data libraries, is utilized to calculate the cold neutron source performance and estimate the nuclear heat load to the cold moderator. The surface source generation capability of MCNPX code has been used to provide the possibility of analyzing different design configurations and perform design optimization analyses with reasonable computer resources. Several design configurations were analyzed and their performance were characterized and optimized.

Using modern methods of reactor physics, we performed full-scale calculations of the Oklo natural reactor. For reliability, we used recent versions of two Monte Carlo codes: the Russian code MCU-REA and the well-known international code MCNP. Both codes produced similar results. We constructed a computer model of the Oklo reactor zone RZ2 which takes into account all details of design and composition. The calculations were performed for three fresh cores with different uranium contents. Multiplication factors, reactivities, and neutron fluxes were calculated. We also estimated the temperature and void effects for the fresh core. As would be expected, we found for the fresh core a significant difference between reactor and Maxwell spectra, which had been used before for averaging cross sections in the Oklo reactor. The averaged cross section of 62149Sm and its dependence on the shift of a resonance position Er (due to variation of fundamental constants) are significantly different from previous results. Contrary to the results of previous papers, we found no evidence of a change of the samarium cross section: a possible shift of the resonance energy is given by the limits -73??Er?62 meV. Following tradition, we have used formulas of Damour and Dyson to estimate the rate of change of the fine structure constant ?. We obtain new, more accurate limits of -4×10-17??·/??3×10-17?yr-1. Further improvement of the accuracy of the limits can be achieved by taking account of the core burn-up. These calculations are in progress.

in the first two years by a study of mechanics, waves, electricity and magnetism, optics, thermal physics with the Faculty of Education and the Faculty of Management. BachelorofScience/BachelorofEducation Physics/ScienceEducation Calendar Year: 2008/2009 Faculty: Arts & Science/Education Advice From the Faculty of Education Choosing

Experimental data bearing on the precision determination of the numerical values of the fundamentalphysical constants are reviewed, with particular emphasis being placed on the identification and isolation of discrepancies and inconsistencies. The purpose of the analysis is to present a consistent set of values of the fundamental constants and to present a careful and complete description of the steps taken to reach this end. The Introduction discusses the significance of such an analysis and indicates the general method of approach. The indispensability of local unit systems and conversion factors connecting them, in order to avoid a sacrifice of precision peculiar to different metrological techniques, is emphasized. The point is stressed that conversion constants introduce the danger of ignoring error-statistical correlations between physically measured quantities, and the effects of such correlations on the assignment of errors is discussed. All available sources of experimental information relative to the necessary input data are presented, and changes in definitions of units since our last review are discussed. After the available stochastic input data have been reviewed and the less reliable items eliminated, the third section examines the remainder for mutual compatibility by means of an analysis of variance in which special criteria for recognizing the incompatibility of a datum are developed, using the analogy of the energy of internal strain introduced in overdetermined mechanical structures. Tables of least-squares adjusted values of fundamental constants and conversion factors of physics and chemistry based on the 1963 adjustment are given. Research pertinent to the constants which has been completed or published subsequent to the 1963 "recommended" adjustment is discussed, and the effect of these on our knowledge of the numerical values of the fundamental constants is presented.

A theory of special inconstancy, in which some fundamentalphysical constants such as the fine-structure and gravitational constants may vary, is proposed in pregeometry. In the special theory of inconstancy, the \\alpha-G relation of \\alpha=3\\pi/[16ln(4\\pi/5GM_W^2)] between the varying fine-structure and gravitaional constants (where M_W is the charged weak boson mass) is derived from the hypothesis that both of these constants are related to the same fundamental length scale in nature. Furthermore, it leads to the prediction of dot{{\\alpha}}/\\alpha=(-0.8\\pm2.5)\\times10^{-14}yr^{-1} from the most precise limit of dot{G}/G=(-0.6\\pm2.0)\\times10^{-12}yr^{-1} by Thorsett, which is not only consistent with the recent observation of dot{{\\alpha}}/\\alpha=(0.5\\pm0.5)\\times10^{-14}yr^{-1} by Webb et al. but also feasible for future experimental tests. Also a theory of general inconstancy, in which any fundamentalphysical constants may vary, is proposed in "more general relativity", by assuming that the space-time is "environment-dependent". In the general theory of inconstancy, the G-\\Lambda\\ relation between the varying gravitational and cosmological constants is derived from the hypothesis that the space-time metric is a function of \\tau, the "environment-coodinate", in addition to x^{\\mu}, the ordinary space-time coodinates. Furthermore, it leads to the prediction of the varying cosmological constant, which is consistent with the present observations. In addition, the latest observation of spatial variation in the fine-structure constant from VLT/UVES of (1.1\\pm 0.2)\\times 10^{-6}GLyr^{-1} by King et al. is suggested to be taken as a clear evidence for environment-dependent fundamentalphysical constants

PHYSICAL REVIEW B VOLUME 25, NUMBER 7 Neutron scattering from paramagnetic bcc 'He 1 APRIL 1982 H is calculated using the self-consistent-phonon (SCP) theory for comparison with proposed neutron scattering excitations or critical scattering will be observable only at very small neutron energy transfers (-0.1 pev

A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

Quantum electrodynamics is the first successful and still the most successful quantum field theory. Simple atoms, being essentially QED systems, allow highly accurate theoretical predictions. Because of their simple spectra, such atoms have been also efficiently studied experimentally frequently offering the most precisely measured quantities. Our review is devoted to comparison of theory and experiment in the field of precision physics of light simple atoms. In particular, we consider the Lamb shift in the hydrogen atom, the hyperfine structure in hydrogen, deuterium, helium-3 ion, muonium and positronium, as well as a number of other transitions in positronium. Additionally to a spectrum of unperturbed atoms, we consider annihilation decay of positronium and the g factor of bound particles in various two-body atoms. Special attention is paid to the uncertainty of the QED calculations due to the uncalculated higher-order corrections and effects of the nuclear structure. We also discuss applications of simple atoms to determination of several fundamental constants.

A 14-MeV deuterium-tritium (D-T) neutron source for accelerated end-of-life testing of fusion reactor materials has been designed on the basis of a linear two-component collisional plasma system. An intense flux (up to 5 {times} 10{sup 18}/m{sup 2}{center dot}s) of 14-MeV neutrons is produced in a fully ionized high-density (n{sub e} {approx equal} 3 {times} 10{sup 21} m{sup {minus}3}) tritium target by transverse injection of 60 MW of neutral beam power. Power deposited in the target is removed by thermal electron conduction to large end chambers, where it is deposited in gaseous plasma collectors. We show in this paper that the major physics issues have now been experimentally demonstrated. These include magnetohydrodynamic (MHD) equilibrium and stability, microstability, startup, fueling, Spitzer electron thermal conductivity, and power deposition in a gaseous plasma collector. However, an integrated system has not been demonstrated. 28 refs., 8 figs., 2 tabs.

by the neutron monitors at Mt. Chacaltaya and Mexico City and by the solar neutron telescopes at Chacaltaya. Angular and energy-dependent neutron emission from solar flare magnetic loops, Astrophys. J. Sup- pl. SerPhysics of ion acceleration in the solar flare on 2005 September 7 determines c-ray and neutron

Nuclear Instruments and Methods in Physics Research A 476 (2002) 565Â­568 Bistable damage in neutronE15 kO cm) diodes was irradiated at room temperature with neutrons from a nuclear reactor to fluences about neutron spectrum, dosimetry and irradiation facility can be found elsewhere [9]. After

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

The 1997/98 Handbook of Chemistry and Physics will contain revised nuclear data information dealing with scattering and absorption properties of neutrons. All of these nuclear data were recently reevaluated. The 2,200 meter per second neutron cross sections and the neutron resonance integrals evaluation was performed in conjunction with the 1997 KAPL Wall-Chart of the Nuclides to insure consistency in the recommended values in the Handbook and on the Chart. The 2,200 meters per second neutron cross sections presented in the Handbook correspond to room temperature neutrons, 20.43 C, or a thermal neutron energy of 0.0253 electron volts, (eV). Neutron resonance integrals are defined over the energy range from 0.5 eV up to 0.1 {times} 10{sup 6} eV. They are averaged over a flux spectrum with a 1/E shape. Evaluated experimental data are derived from either a direct measurement or from 1/E spectrum averaged resonance parameter information. Resonance integrals are presented for neutron capture, charged particle or neutron fission reactions. Thermal neutron scattering is used for the investigation of the static and dynamic properties of condensed matter and it requires a knowledge of neutron scattering lengths. The Handbook presents bound atom neutron coherent scattering lengths in units of fentometers. Stellar slow neutron capture processes occur in a thermal neutron spectrum with temperatures approximately 30 keV. 30 keV Maxwellian averaged neutron cross sections for astrophysical applications are a new parameter presented in the 78th edition of the Handbook. No new parameters will be added to the Table of Isotopes` nuclear information but revised values will be provided for parameters of all known nuclides of the 112 chemical elements.

energy neutrons may penetrate through the shielding and cause nuclear recoils on the detector that may be mistaken for a WIMP interaction event. The purpose of this project was to create a detector that shields as well as tags incoming neutrons to measure...

We review the recently proposed unreduced, complex-dynamical solution to the many-body problem with arbitrary interaction and its application to the unified solution of fundamental problems, including dynamic foundations of causally complete quantum mechanics, relativity, particle properties and cosmology. We first analyse the universal properties of this many-body problem solution without any perturbative reduction and show that the emerging new quality of fundamental dynamic multivaluedness (or redundance) of the resulting system configuration leads to the natural and universal concept of dynamic complexity, chaoticity and fractality of any real system behaviour. We then consider unified features of this complex dynamics. Applications of that universal description to systems at various complexity levels have been performed and in this paper we review those at the lowest, fundamental complexity levels leading to causal understanding of the unified origin of quantum mechanics, relativity (special and general), elementary particles, their intrinsic properties and interactions. One reveals, in particular, the complex-dynamic origin of inertial and gravitational (relativistic) mass without introduction of any additional particle species, fields or dimensions. Other practically important consequences and problem solutions in fundamentalphysics and cosmology are summarised, confirming the efficiency of that unified picture.

2-93 2-93 JANUARY 1993 DOE FUNDAMENTALS HANDBOOK NUCLEAR PHYSICS AND REACTOR THEORY Volume 2 of 2 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal., Springfield, VA 22161. Order No. DE93012223 DOE-HDBK-1019/1-93 NUCLEAR PHYSICS AND REACTOR THEORY ABSTRACT The Nuclear Physics and Reactor Theory Handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and the technical

1-93 1-93 JANUARY 1993 DOE FUNDAMENTALS HANDBOOK NUCLEAR PHYSICS AND REACTOR THEORY Volume 1 of 2 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P.O. Box 62, Oak Ridge, TN 37831. Available to the public from the National Technical Information Services, U.S. Department of Commerce, 5285 Port Royal., Springfield, VA 22161. Order No. DE93012221 DOE-HDBK-1019/1-93 NUCLEAR PHYSICS AND REACTOR THEORY ABSTRACT The Nuclear Physics and Reactor Theory Handbook was developed to assist nuclear

Within the past two and one half years of the project ``Surface Physics With Cold and Thermal Neutron Reflectometry`` a new thermal neutron reflectometer was constructed at the Rhode Island Nuclear Science Center (RINSC). It was used to study various liquid and solid surfaces. Furthermore, neutron reflection experiments were be un at different laboratories in collaboration with Dr. G.P. Fetcher (at Argonne National Laboratory), Dr. T. Russell (IBM Almaden) and Drs. S.K. Satija and A. Karim (at the National Institute for Standards and Technology). The available resources allowed partial construction of an imaging system for ultracold neutrons. It is expected to provide an extremely high resolution in momentum and energy transfer in surface studies using neutron reflectometry. Much of the work reported here was motivated by the possibility of later implementation at the planned Advanced Neutron Source at Oak Ridge. In a separate project the first concrete plans for an intense source of ultracold neutrons for the Advanced Neutron Source were developed.

Research is reported on the physics and chemistry of atoms, ions, and molecules, especially their interactions with external agents such as photons and electrons. Individual items from the report were prepared separately for the data base. (GHT)

Physics analyses have been performed to characterize the performance of the cold neutron source to be installed in the High Flux Isotope Reactor at the Oak Ridge National Laboratory in the near future. This paper provides a description of the physics models developed, and the resulting analyses that have been performed to support the design of the cold source. These analyses have provided important parametric performance information, such as cold neutron brightness down the beam tube and the various component heat loads, that have been used to develop the reference cold source concept.

Precision measurements in free neutron beta decay serve to determine the coupling constants of beta decay, and offer several stringent tests of the Standard Model. This paper describes the free neutron beta decay program planned for the FundamentalPhysics Beamline at the Spallation Neutron Source at Oak Ridge National Laboratory, and puts it into the context of other recent and planned measurements of neutron beta decay observables.

Capabilities of the FNPB Instrument Capabilities of the FNPB Instrument FundamentalPhysics with Cold and Ultracold NeutronsFundamental Beamline The fundamentalphysics beam line showing the "cold neutron" area inside the SNS Experiment Hall and the external UCN facility. For scale, the existing n+ p â d + Î³ apparatus is shown in the "cold beam" position, and the proposed neutron electric dipole moment apparatus is shown in the external building. Cold neutrons and ultracold neutrons (UCNs) have been employed in a wide variety of investigations that shed light on important issues in nuclear, particle, and astrophysics in the determination of fundamental constants and in the study of fundamental symmetry violation. In many cases, these experiments provide information not available from existing

Black holes present the extreme limits of physics. They are ubiquitous in the cosmos, and in some extra-dimensional scenarios they could be produced at colliders. They have also yielded a puzzle that challenges the foundations of physics. These talks will begin with an overview of the basics of black hole physics, and then briefly summarize some of the exciting developments with cosmic black holes. They will then turn to properties of quantum black holes, and the question of black hole production in high energy collisions, perhaps beginning with the LHC. I will then overview the apparent paradox emerging from Hawking's discovery of black hole evaporation, and what it could be teaching us about the foundations of quantum mechanics and gravity.

Black holes present the extreme limits of physics. They are ubiquitous in the cosmos, and in some extra-dimensional scenarios they could be produced at colliders. They have also yielded a puzzle that challenges the foundations of physics. These talks will begin with an overview of the basics of black hole physics, and then briefly summarize some of the exciting developments with cosmic black holes. They will then turn to properties of quantum black holes, and the question of black hole production in high energy collisions, perhaps beginning with the LHC. I will then overview the apparent paradox emerging from Hawking's discovery of black hole evaporation, and what it could be teaching us about the foundations of quantum mechanics and gravity.

Black holes present the extreme limits of physics. They are ubiquitous in the cosmos, and in some extra-dimensional scenarios they could be produced at colliders. They have also yielded a puzzle that challenges the foundations of physics. These talks will begin with an overview of the basics of black hole physics, and then briefly summarize some of the exciting developments with cosmic black holes. They will then turn to properties of quantum black holes, and the question of black hole production in high energy collisions, perhaps beginning with the LHC. I will then overview the apparent paradox emerging from Hawking's discovery of black hole evaporation, and what it could be teaching us about the foundations of quantum mechanics and gravity.

(Abridged) In this paper we present a compilation of results from our most advanced neutron star merger simulations, including a description of the employed numerical procedures and a more complete overview over a large number of computed models. The three-dimensional hydrodynamic simulations were done with a code based on the Piecewise Parabolic Method with up to five levels of nested Cartesian grids. The simulations are basically Newtonian, but gravitational-wave emission and the corresponding back-reaction are taken into account. The use of a physical nuclear equation of state allows us to follow the thermodynamic history of the stellar medium and to compute the energy and lepton number loss due to the emission of neutrinos. The computed models differ concerning the neutron star masses and mass ratios, the neutron star spins, the numerical resolution expressed by the cell size of the finest grid and the number of grid levels, and the calculation of the temperature from the solution of the entropy equation instead of the energy equation. Our simulations show that the details of the gravitational-wave emission are still sensitive to the numerical resolution, even in our highest-quality calculations. The amount of mass which can be ejected from neutron star mergers depends strongly on the angular momentum of the system. Our results do not support the initial conditions of temperature and proton-to-nucleon ratio assumed in recent work for producing a solar r-process pattern for nuclei around and above the A approx 130 peak. The improved models confirm our previous conclusion that gamma-ray bursts are not powered by neutrino emission during the dynamical phase of the merging of two neutron stars.

Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before:the probability of UCN losses from the trap was only 1% of that for neutron beta decay. The neutron lifetime obtained,878.5+/-0.7stat+/-0.3sys s, is the most accurate experimental measurement to date.

Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before: the probability of UCN losses from the trap was only 1% of that for neutron {beta} decay. The neutron lifetime obtained, 878.5{+-}0.7{sub stat}{+-}0.3{sub sys} s, is the most accurate experimental measurement to date.

This document is the twelfth Annual Report of our Fundamental Molecular Physics and Chemistry Program. Scientifically, the work of the program deals with aspects of the physics and chemistry of molecules related to their interactions with photons, electrons, and other external agents. We chose these areas of study in view of our matic goals; that is to say, we chose them so that the eventual outcome of our work meets some of the needs of the US Department of Energy (DOE) and of other government agencies that support our research. First, we endeavor to determine theoretically and experimentally cross sections for electron and photon interactions with molecules, because those cross sections are indispensable for detailed microscopic analyses of the earliest processes of radiation action on any molecular substance, including biological materials. Those analyses in turn provide a sound basis for radiology and radiation dosimetry. Second, we study the spectroscopy of certain molecules and of small clusters of molecules because this topic is fundamental to the full understanding of atmospheric-pollutant chemistry.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamentalneutronphysics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

THE Oregon State University Department of Nuclear Engineering & Radiation Health PhysicsNeutron's Study Abroad Program. Arnold will earn a B.S. in Nuclear Engineering with a minor in French when she graduates this spring. INSIDE Why would a nuclear engineering student add a French minor to an already

Neutron Electric Dipole Moment (nEDM), a generic feature of CP-violation, is predicted to be very small in the Standard Model, but can be much larger in most extensions of the model. In this talk, I will discuss the classification of the CP violating operators up to dimension 6 that can give rise to nEDM, and then describe the mixing and renormalization structure of the operators of dimension 5 and lower in both dimensional and cutoff regularizations in general terms. Finally I will describe how to connect the dimension 5 operators, in particular, the Chromoelectric Dipole Moment of the quarks, between MSbar scheme and a Regularization Independent prescription in the chiral limit.

BNCT is a tumour treatment based on thermal-neutron irradiation of tissues enriched with 10B, which according to the 10B(n, )7Li reaction produces particles with high Linear Energy Transfer and short range. Since this treatment can deliver a therapeutic tumour dose sparing normal tissues, BNCT represents an alternative for diffuse tumours and metastases, which show poor response to surgery and photontherapy. In 2001 and 2003, in Pavia BNCT was applied to an isolated liver, which was infused with boron, explanted, irradiated and re-implanted. A new project was then initiated for lung tumours, developing a protocol for Boron concentration measurements and performing organ-dose Monte Carlo calculations; in parallel, radiobiology studies are ongoing to characterize the BNCT effects down to cellular level. After a brief introduction, herein we will present the main activities ongoing in Pavia including the radiobiological ones, which are under investigation not only experimentally but also theoretically, basing on...

High intense electromagnetic fields can be unique probes to study natures of macroscopic vacua by themselves. Combining accelerators with the intense field can provide more fruitful probes which can neither be achieved by only intense fields nor only high energy accelerators. We will overview the natures of vacua which can be accessible via intense laser-laser and intense laser-electron interactions. In the case of the laser-laser interaction, we propose how to observe nonlinear QED effects and effects of new fields like light scalar and pseudo scalar fields which may contribute to a macroscopic nature of our universe such as dark energy. In the case of the laser-electron interaction, in addition to nonlinear QED effects, we can further discuss the nature of accelerating field in the vacuum where we can access physics related with event horizons such as Hawking-Unruh radiations. We will introduce a recent experimental trial to search for this kind of odd radiations.

We investigate the dynamics and evolution of coalescing neutron stars. Although the code (Piecewise Parabolic Method) is purely Newtonian, we do include the emission of gravitational waves and their backreaction on the hydrodynamic flow. The properties of neutron star matter are described by the physical equation of state of Lattimer \\& Swesty (1991). Energy loss by all types of neutrinos and changes of the electron fraction due to the emission of electron neutrinos and antineutrinos are taken into account by an elaborate ``neutrino leakage scheme''. We simulate the coalescence of two identical, cool neutron stars with a baryonic mass of $\\approx\\!1.6\\,M_\\odot$ and a radius of $\\approx\\!15$~km and with an initial center-to-center distance of 42~km. The initial distributions of density and electron concentration are given from a model of a cold neutron star in hydrostatic equilibrium (central temperature about $8\\,{\\rm MeV}$). We investigate three cases which differ by the initial velocity distribution in the neutron stars, representing different cases of the neutron star spins relative to the direction of the orbital angular momentum vector. Within about 1~ms the neutron stars merge into a rapidly spinning ($P_{\\rm spin}\\approx 1$~ms), high-density body ($\\rho\\approx 10^{14}$~g/cm$^3$) with a surrounding thick disk of material with densities $\\rho\\approx 10^{10}-10^{12}$~g/cm$^3$ and orbital velocities of~0.3--0.5~c. In this work we evaluate the models in detail with respect to the gravitational wave emission using the quadrupole approximation. In a forthcoming paper we will concentrate on the neutrino emission and implications for gamma-ray bursters. A maximum luminosity in excess of $10^{55}$~erg/s is reached for about 1~ms.

Neutron Interferometry: Lessons in Experimental Quantum Mechanics Helmut Rauch and Samuel A. Werner Today, 55, 52 (2002). The copious availability of thermalized neutrons makes them an ideal probe of choice for many fundamentalphysics investigations. A prime example is the field of neutron

gas model) is to assume that a particle experience s collisions per unit time and have a change. The Lorentz gas model can describe well collisions between electron and neutrals, or even between ionsPHYS 626 -- Fundamentals of Plasma Physics -- Section 5.6-5.7 1. A simple collision model (Lorentz

Neutron Basics Neutron Basics A neutron is one of the fundamental particles that make up matter. This uncharged particle exists in the nucleus of a typical atom, along with its positively charged counterpart, the proton. Protons and neutrons each have about the same mass, and both can exist as free particles away from the nucleus. In the universe, neutrons are abundant, making up more than half of all visible matter. Find Out What a Neutron Is Youtube icon Properties of Neutrons How Can Neutrons Be Used for Research? Image of glucose movement in plants Neutron imaging techniques have been able to determine the precise movement of glucose in plants. This knowledge can help scientists better understand how biomass can be efficiently converted into fuel. Neutrons have many properties that make them ideal for certain types of

The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. The neutron lifetime recently obtained, 878.5 +/- 0.7stat +/- 0.3sys s, is the most accurate one to date. The new result for the neutron lifetime differs from the world average value by 6.5 standard deviations. The impact of the new result on testing of Standard Model and on data analysis for the primordial nucleosynthesis model is scrutinized.

I consider the beginning to modern particle physics to be in 1932--33, when James Chadwick discovered the neutron at Cambridge, England, and Carl Anderson discovered the positron in Pasadena, California. I leave out the discoveries of the electron by J. J. Thomson, the nucleus and the proton by Ernest Rutherford, as well as the photon introduced by Albert Einstein and the neutrino as hypothesized by Wolfgang Pauli, as having occurred before my time.'' I was thus able to follow -- and sometimes participate in -- all the developments of modern particle physics. The story I will tell is as the unfolding of the field looked; to me -- an experimental particle physicists. As with Rashomon, this is as I see it. To get a different point of view, and no doubt there are many, you need different observer. One might ask, what did I know about physics in the 1930s, anyway It so happens that I did hear abut Chadwick's discovery at the time, mainly because my brother Maurice was working with him in 1934 on the photo-disintegration of the deuteron, and on the first good measurement of the neutron mass. I will concentrate on the thirty years, 1930 to 1960 which includes Dick Dalitz' important early contributions. I will then skip most of the next thirty years for lack of time, and end up with the study of the Z{sup 0} in e{sup +}e{sup {minus}} annihilation. For more details, and explicit references to published papers, I will refer the reader to a recent book by Robert Cahn and myself.

Most of us consider semiconductors as a very technical subject, thinking of computer chips and all the electronic equipment in the lab and at home. ... some elaborate etching and deposition processes, but "Fundamentals

The dynamics of a physical gel, namely the Low Molecular Mass Organic Gelator {\\textit Methyl-4,6-O-benzylidene-$\\alpha$ -D-mannopyranoside ($\\alpha$-manno)} in water and toluene are probed by neutron scattering. Using high gelator concentrations, we were able to determine, on a timescale from a few ps to 1 ns, the number of solvent molecules that are immobilised by the rigid network formed by the gelators. We found that only few toluene molecules per gelator participate to the network which is formed by hydrogen bonding between the gelators' sugar moieties. In water, however, the interactions leading to the gel formations are weaker, involving dipolar, hydrophobic or $\\pi-\\pi$ interactions and hydrogen bonds are formed between the gelators and the surrounding water. Therefore, around 10 to 14 water molecules per gelator are immobilised by the presence of the network. This study shows that neutron scattering can give valuable information about the behaviour of solvent confined in a molecular gel.

'.. '.. iJNCLASSIFIED . UNITED x STATES ATOMIC ENERGY COMMISSION . 1 I~, ., AECD-2664 ,# NEUTRONPHYSICS A Revision of I. Halpern's Notes on E. Fermi's Lectures in 1945 BY J. G. Beckerley October 16, 1951 [TIS Issuance Date] Atomic Energy Commission New York Operations :L : 't to TIC ;iiiii *=c; Technical Information Service, Oak Ridge, Tennessee . _ .._ U,NCLASSlFIEB DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that

PhysicsPhysicsPhysics Print Because a large proportion of ALS experiments are "physics" experiments, it's useful to separate them into two categories - one focused on Materials/Condensed Matter, and this one, with a dual focus on AMO (atomic, molecular, and optical) physics and accelerator physics. Light sources such as the ALS have opened up research frontiers that may hold the answers to fundamental questions about structure and dynamics in AMO physics. The advanced spectroscopies that have been developed here provide the ability to control and probe atomic and molecular processes with unprecedented precision. In particular, the spectral resolution, brightness, broad tunability, and polarization control generate novel avenues for the study of tailored states, inner-shell processes, and nonperturbative electron interactions. Driven by the high brightness of the ALS, a whole new world of vacuum ultraviolet (VUV) and soft x-ray physics has emerged through the development of combined techniques to excite, select, and probe atoms, molecules, and clusters.

Physics Print Physics Print Because a large proportion of ALS experiments are "physics" experiments, it's useful to separate them into two categories - one focused on Materials/Condensed Matter, and this one, with a dual focus on AMO (atomic, molecular, and optical) physics and accelerator physics. Light sources such as the ALS have opened up research frontiers that may hold the answers to fundamental questions about structure and dynamics in AMO physics. The advanced spectroscopies that have been developed here provide the ability to control and probe atomic and molecular processes with unprecedented precision. In particular, the spectral resolution, brightness, broad tunability, and polarization control generate novel avenues for the study of tailored states, inner-shell processes, and nonperturbative electron interactions. Driven by the high brightness of the ALS, a whole new world of vacuum ultraviolet (VUV) and soft x-ray physics has emerged through the development of combined techniques to excite, select, and probe atoms, molecules, and clusters.

At very high densities, electrons react with protons to form neutron rich matter. This material is central to many fundamental questions in nuclear physics and astrophysics. Moreover, neutron rich matter is being studied with an extraordinary variety of new tools such as the Facility for Rare Isotope Beams (FRIB) and the Laser Interferometer Gravitational Wave Observatory (LIGO). We describe the Lead Radius Experiment (PREX) that uses parity violating electron scattering to measure the neutron radius in 208Pb. This has important implications for neutron stars and their crusts. We discuss X-ray observations of neutron star radii. These also have important implications for neutron rich matter. Gravitational waves (GW) open a new window on neutron rich matter. They come from sources such as neutron star mergers, rotating neutron star mountains, and collective r-mode oscillations. Using large scale molecular dynamics simulations, we find neutron star crust to be very strong. It can support mountains on rotating neutron stars large enough to generate detectable gravitational waves. We believe that combing astronomical observations using photons, GW, and neutrinos, with laboratory experiments on nuclei, heavy ion collisions, and radioactive beams will fundamentally advance our knowledge of compact objects in the heavens, the dense phases of QCD, the origin of the elements, and of neutron rich matter.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

1.1 Nuclear Research Emulsions (NRE) have a long and illustrious history of applications in the physical sciences, earth sciences and biological sciences (1,2) . In the physical sciences, NRE experiments have led to many fundamental discoveries in such diverse disciplines as nuclear physics, cosmic ray physics and high energy physics. In the applied physical sciences, NRE have been used in neutronphysics experiments in both fission and fusion reactor environments (3-6). Numerous NRE neutron experiments can be found in other applied disciplines, such as nuclear engineering, environmental monitoring and health physics. Given the breadth of NRE applications, there exist many textbooks and handbooks that provide considerable detail on the techniques used in the NRE method. As a consequence, this practice will be restricted to the application of the NRE method for neutron measurements in reactor physics and nuclear engineering with particular emphasis on neutron dosimetry in benchmark fields (see Matrix E706). 1...

A modified model is developed for describing the distribution of random resonance width for any nuclei. The model assumes the coexistence in a nucleus of one or several partial radiative and neutron amplitudes for respective resonance widths, these amplitudes differing in their parameters. Also, it is assumed that amplitude can be described by a Gaussian curve characterized by a nonzero mean value and a variance not equal to unity and that their most probable values can be obtained with the highest reliability from approximations of cumulative sums of respective widths. An analysis of data for 157 sets of neutron widths for 0 {<=} l {<=} 3 and for 56 sets of total radiative widths has been performed to date. The basic result of this analysis is the following: both for neutron and for total radiative widths, the experimental set of resonance width can be represented with a rather high probability in the form of a superposition of k {<=} 4 types differing in mean amplitude parameters.

Some tests of fundamentalphysics - the equation of state at supra-nuclear densities, the metric in strong gravity, the effect of magnetic fields above the quantum critical value - can only be measured using compact astrophysical objects: neutron stars and black holes. The Extreme Physics Explorer is a modest sized (~500 kg) mission that would carry a high resolution (R ~300) X-ray spectrometer and a sensitive X-ray polarimeter, both with high time resolution (~5 ?s) capability, at the focus of a large area (~5 sq.m), low resolution (HPD~1 arcmin) X-ray mirror. This instrumentation would enable new classes of tests of fundamentalphysics using neutron stars and black holes as cosmic laboratories.

Microscopic calculations of neutron matter based on nuclear interactions derived from chiral effective field theory, combined with the recent observation of a 1.97 {+-} 0.04 M{sub Sun} neutron star, constrain the equation of state of neutron-rich matter at sub- and supranuclear densities. We discuss in detail the allowed equations of state and the impact of our results on the structure of neutron stars, the crust-core transition density, and the nuclear symmetry energy. In particular, we show that the predicted range for neutron star radii is robust. For use in astrophysical simulations, we provide detailed numerical tables for a representative set of equations of state consistent with these constraints.

Fundamental Particles Fundamental Particles Chart of Fundamental Particles All matter in the universe is comprised of fundamental particles. So what exactly makes up this matter? All matter is made of fundamental particles that came into being at the birth of the Universe. Quarks experience the strong force which is carried by massless particles called gluons. They bond together in specific combinations to form protons, neutrons, and other hadrons. Leptons do not experience the strong force but may interact via the electromagnetic force, the weak force, or both. Anti-quarks and anti-leptons are exactly the same as their quark and lepton counterparts, but have an opposite charge. All massive particles are influenced by the force of gravity. Quark-Gluon Plasma: 10-12 Seconds After the Big Bang

...what remains after such a stars thermonuclear life. The pressure, which like all pressures...peak temperature the integrated core thermonuclear power is smaller than the surface...First, Ms is not determined solely by thermonuclear considerationsphoton opacities...

Neutron Science Neutron Science Neutron Scattering Science Neutrons are one of the fundamental particles that make up matter and have properties that make them ideal for certain types of research. In the universe, neutrons are abundant, making up more than half of all visible matter. Neutron scattering provides information about the positions, motions, and magnetic properties of solids. When a beam of neutrons is aimed at a sample, many neutrons will pass through the material. But some will interact directly with atomic nuclei and "bounce" away at an angle, like colliding balls in a game of pool. This behavior is called neutron diffraction, or neutron scattering. Using detectors, scientists can count scattered neutrons, measure their energies and the angles at which they scatter, and map their final position

This report is composed of the lecture notes from the first half of a 32-hour graduate-level course on Monte Carlo methods offered at KAPL. These notes, prepared by two of the principle developers of KAPL`s RACER Monte Carlo code, cover the fundamental theory, concepts, and practices for Monte Carlo analysis. In particular, a thorough grounding in the basic fundamentals of Monte Carlo methods is presented, including random number generation, random sampling, the Monte Carlo approach to solving transport problems, computational geometry, collision physics, tallies, and eigenvalue calculations. Furthermore, modern computational algorithms for vector and parallel approaches to Monte Carlo calculations are covered in detail, including fundamental parallel and vector concepts, the event-based algorithm, master/slave schemes, parallel scaling laws, and portability issues.

Abstract The latest release of the EMPIRE-3.1 system (codename Rivoli) is being used in the advanced modeling of neutron induced reactions on the 238U nucleus with the aim of improving our knowledge of neutron scattering. The reaction model includes: (i) a new rotational-vibrational dispersive optical model potential coupling the low-lying collective bands of vibrational character observed in even-even actinides, (ii) the Engelbrecht-Weidenmüller transformation allowing for inclusion of compound-direct interference effects enhanced by a dispersive treatment of the optical model potential, (iii) a multi-humped fission barrier with absorption in the secondary well as described within the optical model for fission, and (iv) a modified Lorentzian model (MLO) of the radiative strength function. Impact of the advanced modeling on elastic and inelastic scattering cross section is being assessed by both comparison with selected microscopic experimental data and integral criticality benchmarks (e.g. FLATTOP, JEMIMA and BIGTEN assemblies). Benchmark calculations provide feedback to improve the reaction modeling and reduce both model and model-parameters uncertainties. Additionally, neutron scattering yields on 238U measured accurately at RPI by the time-of-flight technique at 29, 60, 112 and 153 degrees have been used as a further constraint on the incident energy dependence of elastic and inelastically scattered neutrons. Improvement of scattering cross sections in existing libraries is discussed.

DEPARTMENT OF PHYSICS Syllabus Physics 20300 General Physics Designation: Required Undergraduate Catalog description: For majors in the life sciences (biology, medicine, dentistry, psychology, physical therapy) and for liberal arts students. Fundamental ideas and laws of physics from mechanics to modern

The present report documents deliberations of a large group of experts in neutron scattering and fundamentalphysics on the need for new neutron sources of greater intensity and more sophisticated instrumentation than those currently available. An additional aspect of the Workshop was a comparison between steady-state (reactor) and pulsed (spallation) sources. The main conclusions were: (1) the case for a new higher flux neutron source is extremely strong and such a facility will lead to qualitatively new advances in condensed matter science and fundamentalphysics; (2) to a large extent the future needs of the scientific community could be met with either a 5 x 10/sup 15/ n cm/sup -2/s/sup -1/ steady state source or a 10/sup 17/ n cm/sup -2/s/sup -1/ peak flux spallation source; and (3) the findings of this Workshop are consistent with the recommendations of the Major Materials Facilities Committee.

The following chapter illustrates the basic physical processes occurring during laser-material interaction. It considers fundamentals of electrodynamics in relation to electronphonon interaction, electromagne...

The European Spallation Neutron Source (ESS) delivers high-intensity pulsed particle beams with 5-MW average beam power at 1.3-GeV incident proton energy. This causes sophisticated demands on material and geometry choices and a very careful optimization of the whole target system. Therefore, complex and detailed particle transport models and computer code systems have been developed and used to study the nuclear assessment of the ESS target system. The purpose here is to describe the methods of calculation mainly based on the Monte Carlo code to show the performance of the ESS target station. The interesting results of the simulations of the mercury target system are as follows: time-dependent neutron flux densities, energy deposition and heating, radioactivity and afterheat, materials damage by radiation, and high-energy source shielding. The results are discussed in great detail. The validity of codes and models, further requirements to improve the methods of calculation, and the status of running and planned experiments are given also.

Neutron Scattering Neutron Scattering Materials Sciences and Engineering (MSE) Division MSE Home About Research Areas Energy Frontier Research Centers (EFRCs) DOE Energy Innovation Hubs BES Funding Opportunities The Computational Materials and Chemical Sciences Network (CMCSN) Theoretical Condensed Matter Physics Scientific Highlights Reports and Activities Principal Investigators' Meetings BES Home Research Areas Neutron Scattering Print Text Size: A A A RSS Feeds FeedbackShare Page This activity supports basic research on the fundamental interactions of neutrons with matter to achieve an understanding of the atomic, electronic, and magnetic structures and excitations of materials and their relationship to materials properties. Major emphasis is on the application of neutron scattering, spectroscopy, and imaging for materials research, primarily at

The optimization of the ballistic guide design for the SNS FundamentalNeutronPhysics Beamline 8.9 A line is described. With a careful tuning of the shape of the curve for the tapered section and the width of the straight section, this optimization resulted in more than 75% increase in the neutron flux exiting the 33 m long guide over a straight m=3.5 guide with the same length.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs.

The development of the flat moderator concept at ESS recently opened up the possibility that a single flat moderator above the target could serve all the scattering instruments, that rely on high brightness. This would allow for the introduction of a fundamentally different moderator below the target for the complementary needs of certain fundamentalphysics experiments. To facilitate experiments depending on the total number of neutrons in a sizable beam, the option of a voluminous D2 moderator, in a large cross-section extraction guide is discussed and its neutronic performance is assessed.

The development of the flat moderator concept at ESS recently opened up the possibility that a single flat moderator above the target could serve all the scattering instruments, that rely on high brightness. This would allow for the introduction of a fundamentally different moderator below the target for the complementary needs of certain fundamentalphysics experiments. To facilitate experiments depending on the total number of neutrons in a sizable beam, the option of a voluminous D2 moderator, in a large cross-section extraction guide is discussed and its neutronic performance is assessed.

when the beam velocity is greater than the thermal velocity. Physically, large thermal velocity is to have a small component of beam with high beam velocity (much greater than the thermal velocity thermal velocity. Homework #12 (due Friday, December 11th , before class): Problem # 8.16, 8.17, 8

The first two sections of the handbook have introduced the reader to UAVs in ... the way for this third section, UAV Fundamentals, which details those fundamentals that constitute the foundational elements of UAV...

The ICNS provides a focal point for the worldwide neutron user community to strengthen ties within this diverse group, while at the same time promoting neutron research among colleagues in related disciplines identified as Ã?Â¢Ã?Â?Ã?Â?would-beÃ?Â¢Ã?Â?Ã?Â neutron users. The International Conference on Neutron Scattering thus serves a dual role as an international user meeting and a scientific meeting. As a venue for scientific exchange, the ICNS showcases recent results and provides forums for scientific discussion of neutron research in diverse fields such as hard and soft condensed matter, liquids, biology, magnetism, engineering materials, chemical spectroscopy, crystal structure, and elementary excitations, fundamentalphysics and development of neutron instrumentation through a combination of invited talks, contributed talks and poster sessions. Each of the major national neutron facilities (NIST, LANSCE, ANL, HFIR and SNS), along with their international counterparts, has an opportunity to exchange information with each other and to update users, and potential users, of their facility. This is also an appropriate forum for users to raise issues that relate to the facilities.

This study addresses, for the first time, the total prompt energy release and its components for the fission of 235U, 238U, and 239Pu as a function of the kinetic energy of the neutron inducing the fission. The components are extracted from experimental measurements, where they exist, together with model-dependent calculation, interpolation, and extrapolation. While the components display clear dependencies upon the incident neutron energy, their sums display only weak, yet definite, energy dependencies. Also addressed is the total prompt energy deposition in fission for the same three systems. Results are presented in equation form. New measurements are recommended as a consequence of this study.

This paper on ASTROD I is based on our 2010 proposal submitted for the ESA call for class-M mission proposals, and is a sequel and an update to our previous paper [Experimental Astronomy 23 (2009) 491-527; designated as Paper I] which was based on our last proposal submitted for the 2007 ESA call. In this paper, we present our orbit selection with one Venus swing-by together with orbit simulation. In Paper I, our orbit choice is with two Venus swing-bys. The present choice takes shorter time (about 250 days) to reach the opposite side of the Sun. We also present a preliminary design of the optical bench, and elaborate on the solar physics goals with the radiation monitor payload. We discuss telescope size, trade-offs of drag-free sensitivities, thermal issues and present an outlook. ASTROD I is a planned interplanetary space mission with multiple goals. The primary aims are: to test General Relativity with an improvement in sensitivity of over 3 orders of magnitude, improving our understanding of gravity and ...

We continue the study of the neutron-proton system by taking up the well-known problem of neutron scattering in hydrogen. The scattering cross section has been carefully measured to be 20.4 barns over a wide energy range. Our intent is to apply the method of phase shifts summarized in the preceding lecture to this problem. We see very quickly that the s-wave approximation (the condition of interaction at low energy) is very well justified in the neutron energy range of 1- 1000 eV. The scattering-state solution, with E> 0, gives us the phase shift or equivalently the scattering length. This calculation yields a cross section of 2.3 barns which is considerably different from the experimental value. The reason for the discrepancy lies in the fact that we have not taken into account the spin-dependent nature of the n-p interaction. The neutron and proton spins can form two distinct spin configurations, the two spins being parallel (triplet state) or anti-parallel (singlet), each giving rise to a scattering length. When this is taken into account, the new estimate is quite close to the experimental value. The conclusion is therefore that n-p interaction is spin-dependent and that the anomalously large value of the hydrogen scattering cross section for neutrons is really due to this aspect of the nuclear force. For the scattering problem our task is to solve the radial wave equation for s-wave for solutions with E> 0. The interior and exterior solutions have the form ur () = Bsin ( Kr ' ) , r < ro (8.1) and ur () = C sin(

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

D/gim D/gim Spallation Neutron Source SNS is an accelerator-based neutron source. This one-of-a-kind facility pro- vides the most intense pulsed neutron beams in the world. When ramped up to its full beam power of 1.4 MW, SNS will be eight times more powerful than today's best facility. It will give researchers more detailed snapshots of the smallest samples of physical and biological materials than ever before

Optical microscopes are fundamental to any failure analysis laboratory being easy ... to use and understand. However, most professional electronic component failure analysis laboratories employ more specialised ....

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Industry and Neutron Science Industry and Neutron Science Industry and Neutron Science: Working To Make a Match "In fundamental research, we want to know everything. Industry wants to know enough to answer a question." Research Contact: Mike Crawford September 2011, Written by Deborah Counce Mike Crawford and Souleymane Diallo Mike Crawford of Dupont (right) and Souleymane Diallo, instrument scientist for the Backscattering Spectrometer at SNS, prepare a material sample for an experiment on the instrument. Industrial users are starting to eye the potential of neutron science for solving problems that can't be solved in any other way. At the same time, the SNS and HFIR neutron science facilities at ORNL are exploring ways to woo such users and to make a match of it, to the benefit of both.

The present status of the problem of charge dependence is discussed. The information about the neutron-neutron interaction derived from the two-neutron system, three-nucleon systems, final-state interactions in multiparticle reactions, and peripheral processes is critically evaluated. The experimental data indicate the breakdown of charge independence by about 3-5%. Evidence concerning the violation of charge symmetry is inconclusive, but it seems that most of the data are consistent with the assumption that charge symmetry is satisfied within 0.5-1%. The most suitable studies which might improve the knowledge of the neutron-neutron forces are indicated.

Fundamental Aeronautics Hypersonics Project Reference Document Principal Investigator: James and detailed content of a comprehensive Fundamental Aeronautics Hypersonics research project. It contains) Hypersonic Project is based on the fact that all access to earth or planetary orbit, and all entry into earth

The ACNS provides a focal point for the national neutron user community to strengthen ties within this diverse group, while at the same time promoting neutron research among colleagues in related disciplines identified as would-be neutron users. The American Conference on Neutron Scattering thus serves a dual role as a national user meeting and a scientific meeting. As a venue for scientific exchange, the ACNS showcases recent results and provides forums for scientific discussion of neutron research in diverse fields such as hard and soft condensed matter, liquids, biology, magnetism, engineering materials, chemical spectroscopy, crystal structure, and elementary excitations, fundamentalphysics and development of neutron instrumentation through a combination of invited talks, contributed talks and poster sessions. As a super-user meeting, the ACNS fulfills the main objectives of users' meetings previously held periodically at individual national neutron facilities, with the advantage of a larger and more diverse audience. To this end, each of the major national neutron facilities (NIST, LANSCE, HFIR and SNS) have an opportunity to exchange information and update users, and potential users, of their facility. This is also an appropriate forum for users to raise issues that relate to the facilities. For many of the national facilities, this super-user meeting should obviate the need for separate user meetings that tax the time, energy and budgets of facility staff and the users alike, at least in years when the ACNS is held. We rely upon strong participation from the national facilities. The NSSA intends that the American Conference on Neutron Scattering (ACNS) will occur approximately every two years, but not in years that coincide with the International or European Conferences on Neutron Scattering. The ACNS is to be held in association with one of the national neutron centers in a rotating sequence, with the host facility providing local organization and planning assistance. Additional logistical support is being provided this year through a partnership with the conferencing office of the Materials Research Society (MRS). The ACNS, targeting the entire potential neutron North American user community, complements the annual NIST, ANL and LANSCE neutron and scattering schools which give hands-on experience primarily to graduate students who anticipate using neutron scattering in their thesis research. The summer schools are promoted at the ACNS and represent a natural path for students to take after being inspired by the activities of the ACNS.

of the Neutron Scattering Spectrum from 238 U and Comparison of the Results with a Calculation at the 36.68-e, in final form 22 July 2009) Neutrons elastically scattered from 238 U were measured in the neutron energy neutrons were measured at 25.5 m from the U sample by using a 6 Li detector, and the scattering direction

Clifford Shull, Neutron Diffraction, and Neutron Scattering Clifford Shull, Neutron Diffraction, and Neutron Scattering Resources with Additional Information Clifford G. Shull was awarded the 1994 Nobel Prize in Physics "for the development of the neutron diffraction technique". 'Professor Shull's prize was awarded for his pioneering work in neutron scattering, a technique that reveals where atoms are within a material like ricocheting bullets reveal where obstacles are in the dark. Clifford Shull Photo Courtesy of Oak Ridge National Laboratory When a beam of neutrons is directed at a given material, the neutrons bounce off, or are scattered by, atoms in the sample being investigated. The neutrons' directions change, depending on the location of the atoms they hit, and a diffraction pattern of the atoms' positions can then be obtained.

Eugene Wigner and Fundamental Symmetry Principles Eugene Wigner and Fundamental Symmetry Principles Patents Â· Resources with Additional Information Â· Wigner Honored "[Eugene P.] Wigner's great contribution to science, for which he won the Nobel Prize in Physics in 1963, was his insight into the fundamental mathematics and physics of quantum mechanics. He applied and extended the mathematical theory of groups to the quantum world of the atom; specifically, he used group theory to organize the quantum energy levels of electrons in atoms in a way that is now standard. With that mathematical approach to the atom, Wigner became one of the first to apprehend the deep implications of symmetry, which has since emerged as one, if not the, key principle of 20th-century theoretical physics. ... Eugene P. Wigner

... non-metallic materials, to a final section on contracts, and certainly deals with the fundamental subjects required by the engineer. The forty authors responsible for this work have been ... due attention.

This chapter describes the fundamentals of interfaces between graphics adapters (or graphics controllers) as signal sources and the input of display modules. We distinguish between analog and digital transmiss...

The purpose of this chapter is to review briefly the fundamental principles and methods of RMA. We assume that you have prior knowledge of RMA and require only a refresher. If you require more than a refresher...

The aim of this chapter is to provide a brief survey of the fundamentals of spherical astronomy. This is a field that today is often neglected, although it is in fact still the foundation of many branches of a...

This chapter gives a description and overview of power electronic technologies including a description of the fundamental systems that are the building blocks of power electronic systems. Technologies that are de...

Wireless Sensor Network Fundamentals Wireless Sensor Network Fundamentals Speaker(s): Steven Lanzisera Date: February 8, 2010 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Kevin Kircher Wireless sensor networks have been promising to provide easy data collection and control capability to applications ranging from scientific data collection, disaster recover, national security, and more. The user experience, however, has been filled with confusing terminology, complicated systems, and a lack of interoperability between vendors. Users with a background in the technology and fundamentals are better able to understand system capabilities, make decisions, and end up with a network that meets their needs. Although a sufficient coverage of this topic is at least a semester course, the goal of this talk is to give a brief

...1. Introduction The fundamental constants appear as parameters...least-squares adjustment of the fundamental constants (Mohr Taylor...are the following: How does theory enter into the CODATA evaluation of the fundamental constants? What are the...

We describe recent progress towards deriving the Fundamental Laws of thermodynamics (the 0th, 1st and 2nd Law) from nonequilibrium quantum statistical mechanics in simple, yet physically relevant models. Along the way, we clarify some basic thermodynamic notions and discuss various reversible and irreversible thermodynamic processes from the point of view of quantum statistical mechanics.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

HUD's Eastern Woodlands Office of Native American Programs in collaboration with the Seminole Tribe of Florida Native Learning Center invites you to attend the Procurement Fundamentals training instructed by Vince Franco, Compliance & Resource Development Director of the Native Learning Center in Atlanta, Georgia on September 8-9, 2014.

9 9 Notes: One can use a simple model to deal with price/fundamental relationships. This one predicts monthly average WTI price as a function of OECD total petroleum stock deviations from the normal levels . The graph shows the model as it begins predicting prices in 1992. It shows how well the model has predicted not only the direction, but the magnitude of prices over this 8+ year period. While the model is simple and not perfect, it does predict the overall trends and, in particular, the recent rise in prices. It also shows that prices may have over-shot the fundamental balance for a while -- at least partially due to speculative concerns over Mideast tensions, winter supply adequacy, and Iraq's export policies. Prices now seem to be correcting, and may even undershoot briefly

In the original paper entitled, "Masses of Fundamental Particles"(arXiv:1109.3705v5, 10 Feb 2012), not only the masses of fundamental particles including the weak bosons, Higgs boson, quarks, and leptons, but also the mixing angles of quarks and those of neutrinos are all explained and/or predicted in the unified composite models of quarks and leptons successfully. In this addendum entitled, "Higgs Boson Mass in the Minimal Unified Subquark Model", it is emphasized that the Higgs boson mass is predicted to be about 130Gev in the minimal unified subquark model, which agrees well with the experimental values of 125-126GeV recently found by the ATLAS and CMS Collaborations at the LHC.

Pilot innovative facility for neutron capture therapy was built at Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using 7Li(p,n)7Be threshold reaction. The results of the first experiments on neutron generation are reported and discussed.

Neutron Reflectivity ... This article is part of the Neutron Reflectivity special issue. ... The articles in this special issue on neutron reflectivity cover a broad range of the applications of this technique and the related X-ray and neutron scattering experiments of SAXS, SANS, GISAXS, and GISANS. ...

Adhesion is the interaction that develops between two dissimilar bodies when they are contacted. Adhesion is thus a multidisciplinary science dealing with the chemistry and physics of surfaces and interfaces a...

TEXAS A&M UNIVERSITY LIBRARY ANALOG COMPUTER FUNDAMENTALS Rc APPLICATION A Technical RePort by R. N. PATE L submitted to PROD J. H. CADDESS In n art i a 1 fulf i lment of the requi. rements for the degree of MASTER OF ENGINEERING TEXAS A...-linear operation which is necessary on a general purpose computer. A "quarter-square" tech- -nique is used to effect this operation, use being made of the identity: X7 = 'j?'P(?J3 -c~-~)3 The connections shown i. n figure be made to the patch panel...

For the purposes of this workshop the term fundamentals was taken to mean the basic science (of a chemical and physical nature) underlying the engineering side of thermochemical biomass conversion. The variety ...

The fundamental assumption in Lubrication Theory. Derivation of thin film flow equations from Navier-Stokes equations. Importance of fluid inertia effects in thin film flows. Some fluid physical properties...

Neutron-Proton Exchange Demonstrated ... EVIDENCE of the exchange of charge between protons and neutrons has recently been obtained from studies in the high power cyclotron, according to Ernest O. Lawrence, professor of physics at the University of California a* Berkeley. ...

The discovery of neutrino masses has provided strong hints in favor of the possibility that B-L symmetry is an intimate feature of physics beyond the standard model. I discuss how important information about this symmetry as well as other scenarios for TeV scale new physics can be obtained from the baryon number violating process, neutron-anti-neutron oscillation. This article presents an overview of different aspects of neutron-anti-neutron oscillation and is divided into the following parts : (i) the phenomenon; (ii) the physics, (iii) plausible models and (iv) applications to cosmology. In particular, it is argued how the discovery of $n-\\bar{n}$ oscillation can significantly affect our thinking about simple grand unified theory paradigms for physics beyond the standard model, elucidate the nature of forces behind neutrino mass and provide a new microphysical view of the origin of matter in the universe.

Subatomic Physics Subatomic PhysicsPhysics home Â» Subatomic Physics Site Home About Us Groups Applied Modern Physics, P-21 Neutron Science and Technology, P-23 Plasma Physics, P-24 Subatomic Physics, P-25 CONTACTS Group Leader Jon Kapustinsky (Acting) Deputy Group Leader Andy Saunders Office Administration Irene Martinez Miquela Sanchez Group Office (505) 667-6941 Physics Links Jobs in Physics Human Resources Working at Los Alamos Los Alamos resources Who we are, what we do We conduct basic research in nuclear and particle physics, applying this expertise to solve problems of national importance. By pushing the limits of our understanding of the smallest building blocks of matter through diverse experiments probing aspects of subatomic reactions, we aim to provide a more thorough understanding of the basic

The proposed program is an experimental study of the fundamental properties of Abrikosov vortex matter in type-II superconductors. Most superconducting materials used in applications such as MRI are type II and their transport properties are determined by the interplay between random pinning, interaction and thermal fluctuation effects in the vortex state. Given the technological importance of these materials, a fundamental understanding of the vortex matter is necessary. The vortex lines in type-II superconductors also form a useful model system for fundamental studies of a number of important issues in condensed matter physics, such as the presence of a symmetry-breaking phase transition in the presence of random pinning. Recent advances in neutron scattering facilities such as the major upgrade of the NIST cold source and the Spallation Neutron Source are providing unprecedented opportunities in addressing some of the longstanding issues in vortex physics. The core component of the proposed program is to use small angle neutron scattering and Bitter decoration experiments to provide the most stringent test of the Bragg glass theory by measuring the structure factor in both the real and reciprocal spaces. The proposed experiments include a neutron reflectometry experiment to measure the precise Q-dependence of the structure factor of the vortex lattice in the Bragg glass state. A second set of SANS experiments will be on a shear-strained Nb single crystal for testing a recently proposed theory of the stability of Bragg glass. The objective is to artificially create a set of parallel grain boundaries into a Nb single crystal and use SANS to measure the vortex matter diffraction pattern as a function of the changing angle between the applied magnetic field to the grain boundaries. The intrinsic merits of the proposed work are a new fundamental understanding of type-II superconductors on which superconducting technology is based, and a firm understanding of phases and phase transitions in condensed matter systems with random pinning. The broader impact of the program includes the training of future generation of neutron scientists, and further development of neutron scattering and complementary techniques for studies of superconducting materials. The graduate and undergraduate students participating in this project will learn the state-of-the-art neutron scattering techniques, acquire a wide range of materials research experiences, and participate in the frontier research of superconductivity. This should best prepare the students for future careers in academia, industry, or government.

Education banner Education banner Sunil Sinha A Chat with Sunil Sinha, Distinguished Professor of Physics at the University of California-San Diego and speaker at the recent CNMS-SNS Research Forum more... The purpose of the Spallation Neutron Source and the High Flux Isotope Reactor is to facilitate neutron scattering as an integral tool for scientific research and technological development across many scientific and engineering domains within the scientific, academic,and industrial communities. Coupled with this role is a recognized need to inspire, educate, and facilitate the next generation of users and hence foster enhanced use of the unique neutron scattering facilities at ORNL. This is the central theme of the education activities within the Neutron Sciences Directorate (NScD).

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Abstract Construction is completed and commissioning is in progress for an ultracold neutron (UCN) source at the PULSTAR reactor on the campus of North Carolina State University. The source utilizes two stages of neutron moderation, one in heavy water at room temperature and the other in solid methane at ~ 40 K , followed by a converter stage, solid deuterium at 5 K, that allows a single down scattering of cold neutrons to provide UCN. The UCN source rolls into the thermal column enclosure of the PULSTAR reactor, where neutrons will be delivered from a bare face of the reactor core by streaming through a graphite-lined assembly. The source infrastructure, i.e., graphite-lined assembly, heavy-water system, gas handling system, and helium liquefier cooling system, has been tested and all systems operate as predicted. The research program being considered for the PULSTAR UCN source includes the physics of UCN production, fundamental particle physics, and material surface studies of nanolayers containing hydrogen. In the present paper we report details of the engineering and cryogenic design of the facility as well as results of critical commissioning tests without neutrons.

The final-state interaction of the two neutrons from the reaction ?-+d?2n+? has a pronounced and distinctive effect on the momentum spectrum of the outgoing particles. In particular, the neutron spectrum is sharply peaked in the neighborhood of 2 Mev, with a shape that is quite sensitive to the strength of the nn interaction. In the region of this peak, the relative neutron-neutron momentum is so small that the nn interaction is completely characterized by its scattering length. Hence it is proposed that a measurement of the shape of the neutron spectrum from this reaction may provide a convenient means of measuring the neutron-neutron scattering length. Neutron spectra are calculated in an impulse approximation, for several assumed values of the scattering length. It appears from their shapes that, in this way, present neutron-detection techniques should be capable of determining the scattering length to within 25%.

We will discuss the scientific program to be studied in a new gravitational spectrometer GRANIT in a broad context of quantum states (quantum behaviour) of ultracold neutrons (UCN) in gravitational [1] and centrifugal [2] potentials, as well as applications of these phenomena/spectrometer to various domains of physics, ranging from studies of fundamental short-range interactions and symmetries to neutron quantum optics and reflectometry using UCN. All these topics, as well as related instrumental and methodical developments have been discussed during dedicated GRANIT-2010 Workshop [3]. The GRANIT spectrometer has been recently installed at the Institut Laue-Langevin, Grenoble, France [4] and could become operational in near future. 1. V.V. Nesvizhevsky et al (2002), Nature 415, 297. 2. V.V. Nesvizhevsky et al (2010), Nature Physics 6, 114. 3. GRANIT-2010, Les Houches, 14-19 february 2010. 4. M. Kreuz et al (2009), NIM 611, 326.

The Advanced Neutron Source (ANS) is being designed as a user-oriented neutron research laboratory centered around the most intense continuous beams of thermal and subthermal neutrons in the world. The ANS will be built around a new research reactor of {approximately} 330 MW fission power, producing an unprecedented peak thermal flux of > 7 {times} 10{sup 19} M{sup {minus}2} {center_dot} S{sup {minus}1}. Primarily a research facility, the ANS will accommodate more than 1000 academic, industrial, and government researchers each year. They will conduct basic research in all branches of science-as well as applied research-leading to better understanding of new materials, including high temperature super conductors, plastics, and thin films. Some 48 neutron beam stations will be set up in the ANS beam rooms and the neutron guide hall for neutron scattering and for fundamental and nuclear physics research. There also will be extensive facilities for materials irradiation, isotope production, and analytical chemistry. The R&D program will focus on the four objectives: Address feasibility issues; provide analysis support; evaluate options for improvement in performance beyond minimum requirements; and provide prototype demonstrations for unique facilities. The remainder of this report presents (1) the process by which the R&D activities are controlled and (2) a discussion of the individual tasks that have been identified for the R&D program, including their justification, schedule and costs. The activities discussed in this report will be performed by Martin Marietta Energy Systems, Inc. (MMES) through the Oak Ridge National Laboratory (ORNL) and through subcontracts with industry, universities, and other national laboratories. It should be noted that in general a success path has been assumed for all tasks.

The Advanced Neutron Source (ANS) is being designed as a user-oriented neutron research laboratory centered around the most intense continuous beams of thermal and subthermal neutrons in the world. The ANS will be built around a new research reactor of [approximately] 330 MW fission power, producing an unprecedented peak thermal flux of > 7 [times] 10[sup 19] M[sup [minus]2] [center dot] S[sup [minus]1]. Primarily a research facility, the ANS will accommodate more than 1000 academic, industrial, and government researchers each year. They will conduct basic research in all branches of science-as well as applied research-leading to better understanding of new materials, including high temperature super conductors, plastics, and thin films. Some 48 neutron beam stations will be set up in the ANS beam rooms and the neutron guide hall for neutron scattering and for fundamental and nuclear physics research. There also will be extensive facilities for materials irradiation, isotope production, and analytical chemistry. The R D program will focus on the four objectives: Address feasibility issues; provide analysis support; evaluate options for improvement in performance beyond minimum requirements; and provide prototype demonstrations for unique facilities. The remainder of this report presents (1) the process by which the R D activities are controlled and (2) a discussion of the individual tasks that have been identified for the R D program, including their justification, schedule and costs. The activities discussed in this report will be performed by Martin Marietta Energy Systems, Inc. (MMES) through the Oak Ridge National Laboratory (ORNL) and through subcontracts with industry, universities, and other national laboratories. It should be noted that in general a success path has been assumed for all tasks.

A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

22 February 1949 research-article Neutron Diffraction G. E. Bacon J. Thewlis The problem of neutron diffraction by crystals is treated by analogy...deals with a comparison between X-ray and neutron diffraction and it is shown that quantitatively...

The expected or mean neutron number (or density) provides an adequate characterization of the neutron population and its dynamical excursions in most neutronic applications, in particular power reactors. Fluctuations in the neutron number, originating from the inherent randomness of neutron interactions and fission neutron multiplicities, are relatively small and ignorable for operational purposes, although measurements of the variance and time correlations provide valuable diagnostic information on fundamental reactor physics parameters. However, it is well known that there exist situations of great interest and importance in which a strictly deterministic description, or even one supplemented with a knowledge of low order statistical averages (variance, correlation), provides an incomplete and very unsatisfactory description of the state of the neutron population. These situations are marked by persistent large fluctuations in the neutron number where the emergence of a deterministic phase is suppressed. Such situations are strongly stochastic and therefore unpredictable (i.e., the mean is not representative of the actual population), and can arise either by design or by accident. Examples where the stochastic behavior of neutron populations must be taken into account include: nuclear weapon single-point safety assessment; criticality excursions in spent fuel storage and in the handling of fissile solutions in fuel fabrication and reprocessing; approach to critical under suboptimal reactor start-up conditions; preinitiation in fast burst research reactors; and weak nuclear signatures in the passive detection of nuclear materials. What distinguishes strongly stochastic neutronic systems from strongly deterministic systems is that, in the former, neutron multiplication occurs in the presence of weak neutron sources, such as spontaneous fission and background (cosmic) radiation. Weak sources (in a sense that can be made quite precise) lead to well separated fission chains (a fission chain is defined as the initial source neutron and all its subsequent progeny) in which some chains are short lived while others propagate for unusually long times. Under these conditions, fission chains do not overlap strongly and this precludes the cancellation of neutron number fluctuations necessary for the mean to become established as the dominant measure of the neutron population. The fate of individual chains then plays a defining role in the evolution of the neutron population in strongly stochastic systems, and of particular interest and importance in supercritical systems is the extinction probability, defined as the probability that the neutron chain (initiating neutron and its progeny) will be extinguished at a particular time, or its complement, the time-dependent survival probability. The time-asymptotic limit of the latter, the probability of divergence, gives the probability that the neutron population will grow without bound, and is more commonly known as the probability of initiation or just POI. The ability to numerically compute these probabilities, with high accuracy and without overly restricting the underlying physics (e.g., fission neutron multiplicity, reactivity variation) is clearly essential in developing an understanding of the behavior of strongly stochastic systems.

Neutron scattering is a powerful technique that can be used to probe the structures and dynamics of complex systems. It can provide a fundamental understanding of the processes involved in the production of biofuels from lignocellulosic biomass. A variety of neutron scattering technologies are available to elucidate both the organization and deconstruction of this complex composite material and the associations and morphology of the component polymers and the enzymes acting on them, across multiple length scales ranging from Angstroms to micrometers and time scales from microseconds to picoseconds. Unlike most other experimental techniques, neutron scattering is uniquely sensitive to hydrogen (and its isotope deuterium), an atom abundantly present throughout biomass and a key effector in many biological, chemical, and industrial processes for producing biofuels. Sensitivity to hydrogen, the ability to replace hydrogen with deuterium to alter scattering levels, the fact that neutrons cause little or no direct radiation damage, and the ability of neutrons to exchange thermal energies with materials, provide neutron scattering technologies with unique capabilities for bioenergy research. Further, neutrons are highly penetrating, making it possible to employ sample environments that are not suitable for other techniques. The true power of neutron scattering is realized when it is combined with computer simulation and modeling and contrast variation techniques enabled through selective deuterium labeling.

NEUTRONS AND 2 D ADSORBED PHASES. NEUTRON SCATTERING FROM 36ArAND 4HeFILMS K. CARNEIRO Physics. - The technique of neutron scattering is well established as a unique tool to investigate the details technique to physisorbed phases is quite natural. But on the other hand since neutron scattering, compared

The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

Hot neutron star in generalized thermo-statistics K. Miyazaki E-mail: miyazakiro@rio.odn.ne.jp Abstract The hot neutron star (NS) is investigated for the ...rst time in the generalized thermo-statistics. The study of neutron star (NS) is an important subject in nuclear physics and astro- physics. The equation

7 7 Staff Awards: 2007 Chakoumakos elected MSA Fellow Bryan Chakoumakos Neutron scientist Bryan Chakoumakos was recently elected a fellow of the Mineralogical Society of America. A member of the Neutron Scattering Science Division, Bryan leads the Single-Crystal Diffraction Group. The group has five neutron scattering instruments in various stages of design and construction, located at HFIR and SNS. The MSA was founded in 1919 and, among other goals, encourages fundamental research on natural materials and supports education through its publications, educational grants, and courses. Pharos Neutron Detector System Researchers at the Department of Energy's Oak Ridge National Laboratory have won six R&D 100 Awards, given annually by R&D Magazine to the year's

Background: The neutron skin of a heavy nucleus as well as many neutron-star properties are highly sensitive to the poorly constrained density dependence of the symmetry energy.Purpose: To provide for the first time meaningful theoretical errors and to assess the degree of correlation between the neutron-skin thickness of 208Pb and several neutron-star properties.Methods: A proper covariance analysis based on the predictions of an accurately calibrated relativistic functional FSUGold is used to quantify theoretical errors and correlation coefficients.Results: We find correlation coefficients of nearly 1 (or ?1) between the neutron-skin thickness of 208Pb and a host of observables of relevance to the structure, dynamics, and composition of neutron stars.Conclusions: We suggest that a follow-up Lead Radius Experiment (PREX) measurement, ideally with a 0.5% accuracy, could significantly constrain the equation of state of neutron-star matter.

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 11 8 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non?neutron and neutron nuclear data. Data on the discovery of element 110 Darmstadtium and element 111 have been officially accepted while data on element 118 have been withdrawn. Data to be presented include revised values for very short?lived nuclides long?lived nuclides and beta?beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half?lives which distinguishes between sf decay half?lives and cluster decay half?lives and with cluster?fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor?spectrum which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement using neutron activation analysis will be discussed.

Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern science, ranging from large-scale structures and dynamics of polymers and biological systems, to electronic properties of today's technological materials. Neutron scattering developed into a vast field, encompassing many different experimental techniques aimed at exploring different aspects of matter's atomic structure and dynamics. Modern magnetic neutron scattering includes several specialized techniques designed for specific studies and/or particular classes of materials. Among these are magnetic reflectometry aimed at investigating surfaces, interfaces, and multilayers, small-angle scattering for the large-scale structures, such as a vortex lattice in a superconductor, and neutron spin-echo spectroscopy for glasses and polymers. Each of these techniques and many others offer exciting opportunities for examining magnetism and warrant extensive reviews, but the aim of this chapter is not to survey how different neutron-scattering methods are used to examine magnetic properties of different materials. Here, we concentrate on reviewing the basics of the magnetic neutron scattering, and on the recent developments in applying one of the oldest methods, the triple axis spectroscopy, that still is among the most extensively used ones. The developments discussed here are new and have not been coherently reviewed. Chapter 2 of this book reviews magnetic small-angle scattering, and modern techniques of neutron magnetic reflectometry are discussed in Chapter 3.

The measurement of the distribution of kinetic energy carried by neutron particles is of interest to the health physics and radiation protection industry. Neutron particle spectral fluence is essential to the calculation of absorbed dose, equivalent...

Neutron matter is an intriguing nuclear system with multiple connections to other areas of physics. Considerable progress has been made over the last two decades in exploring the properties of pure neutron fluids. Here we begin by reviewing work done to explore the behavior of very low density neutron matter, which forms a strongly paired superfluid and is thus similar to cold Fermi atoms, though at energy scales differing by many orders of magnitude. We then increase the density, discussing work that ties the study of neutron matter with the determination of the properties of neutron-rich nuclei and neutron-star crusts. After this, we review the impact neutron matter at even higher densities has on the mass-radius relation of neutron stars, thereby making contact with astrophysical observations.

All the materials and living objects around us are composed of atoms. Atoms consist of three main particles that are positively charged protons, negatively charged electrons, and neutrons without any charge. T...

On the basis of current physical understanding, it is impossible to predict with confidence the interior constitution of neutron stars. Cooling of neutron stars provides a possible way of discriminating among possible states of matter within them. In the standard picture of cooling by neutrino emission developed over the past quarter of a century, neutron stars are expected to cool relatively slowly if their cores are made up of nucleons, and to cool faster if matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been called into question by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.

F/gim F/gim Spallation Neutron Source The Spallation Neutron Source (SNS) gives researchers more detailed informa- tion on the structure and dynamics of physical and biological materials than ever before possible. This accelerator- based facility provides the most intense pulsed neutron beams in the world. Scien- tists are able to count scattered neutrons, measure their energies and the angles at which they scatter, and map their final positions. SNS enables measurements of greater sensitivity, higher speed, higher resolution, and in more complex sample environments than have been possible at existing neutron facilities. Future Growth SNS was designed from the outset to accommodate a second target station, effectively doubling the capacity of the

The scientific interest in the resonance neutron induced capture and fission reactions on 239Pu is continuously rising during the last decade. From a practical point of view, this is because more precise data on capture and fission cross sections, fission fragment mass and kinetic energy distributions, variation of prompt fission neutron and gamma yields in the resonance neutron region, are needed for the modelling of new generation nuclear power plants and for nuclear spent fuel and waste transmutation. From a heuristic and fundamental point of view, such a research improves our knowledge and understanding of the fission phenomena itself. To achieve these goals more powerful neutron sources and more precise fission product detectors have to be used. At the Joint Institute for Nuclear Research (JINR) Frank Laboratory of NeutronPhysics (FLNP), where already half a century the thermal and resonance neutron induced nuclear reactions are studied, a new electron accelerator driven white spectrum pulsed neutron source IREN has been built and successfully tested. The improved characteristics of this facility, in comparison with those of the former pulse neutron fast reactor IBR-30, will allow measuring some of the neutron-nuclear reaction data with better precision and accuracy. A new experimental setup for detecting gamma rays (and neutrons) has been designed and is under construction. It will consist of 2 rings (arrays) of 12 NaI(Tl) detectors each (or 1 array of 24 detectors) with variable ring diameter and distance between both rings. Such a setup will make possible not only to measure the multiplicity, energy and angular anisotropy of prompt fission gammas, but also to separate the contribution of prompt fission neutrons by their longer time-of-flight from the fissile target to the detectors. The signals from all the 24 detectors will be recorded simultaneously in digitized form and will be stored on the hard disk of the personal computer for further off-line analysis. The measurement of the prompt gamma-ray emission from 239Pu resonance neutron induced fission is one of the most probable candidates for the first experiments to be performed at IREN using the newly designed gamma-ray detector.

We report successful operation of a neutron microscope using ultracold neutrons at the high-flux reactor at Grenoble. A sharp, achromatic image of an object slit was obtained at a magnification of 50. The measured resolution of 0.1 mm was limited mainly by the available beam intensity, not by aberrations.

... statements that the EMBL outstation in Grenoble "[has an] uncertain future" and that "neutrons have not turned out to be particularly useful for biologists" in Peter Newmark's ... on the European Molecular Biology Laboratory (Nature 338, 724; 1989) require some comment.Neutron ...

A detailed understanding of fundamental material properties can be obtained through the study of atomic vibrations, performed experimentally with neutron scattering techniques and coupled with the two powerful new computational methodologies I have...

Molecular Fundamentals of Enzyme Nanogels ... In addition to the H-bond, a static electronic force or hydrophobic interactions may also be anticipated to create a monomer?enzyme assembly and fabricate various enzyme nanogels and thus merit further efforts. ... Combinatorial approaches are increasingly applied in the design of robust immobilized enzymes by rational combination of fundamental immobilization techniques (i.e., non-covalent adsorption, covalent binding, entrapment, and encapsulation) or with other relevant technologies. ...

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

This research focuses on fundamental processes in plasmas, and emphasizes problems for which precise experimental tests of theory can be obtained. Experiments are performed on non-neutral plasmas, utilizing three electron traps and one ion trap with a broad range of operating regimes and diagnostics. Theory is focused on fundamental plasma and fluid processes underlying collisional transport and fluid turbulence, using both analytic techniques and medium-scale numerical simulations. The simplicity of these systems allows a depth of understanding and a precision of comparison between theory and experiment which is rarely possible for neutral plasmas in complex geometry. The recent work has focused on three areas in basic plasma physics. First, experiments and theory have probed fundamental characteristics of plasma waves: from the low-amplitude thermal regime, to inviscid damping and fluid echoes, to cold fluid waves in cryogenic ion plasmas. Second, the wide-ranging effects of dissipative separatrices have been studied experimentally and theoretically, finding novel wave damping and coupling effects and important plasma transport effects. Finally, correlated systems have been investigated experimentally and theoretically: UCSD experients have now measured the Salpeter correlation enhancement, and theory work has characterized the 'guiding center atoms of antihydrogen created at CERN.

From 2007 to the present, the Remote Sensing Laboratory has been conducting a series of studies designed to expand our fundamental understanding of aerial neutron detection with the goal of designing an enhanced sensitivity detection system for long range neutron detection. Over 35 hours of aerial measurements in a helicopter were conducted for a variety of neutron emitters such as neutron point sources, a commercial nuclear power reactor, nuclear reactor spent fuel in dry cask storage, depleted uranium hexafluoride and depleted uranium metal. The goals of the project were to increase the detection sensitivity of our instruments such that a 5.4 × 104 neutron/second source could be detected at 100 feet above ground level at a speed of 70 knots and to enhance the long-range detection sensitivity for larger neutron sources, i.e., detection ranges above 1000 feet. In order to increase the sensitivity of aerial neutron detection instruments, it is important to understand the dynamics of the neutron background as a function of altitude. For aerial neutron detection, studies have shown that the neutron background primarily originates from above the aircraft, being produced in the upper atmosphere by galactic cosmic-ray interactions with air molecules. These interactions produce energetic neutrons and charged particles that cascade to the earths surface, producing additional neutrons in secondary collisions. Hence, the neutron background increases as a function of altitude which is an impediment to long-range neutron detection. In order to increase the sensitivity for long range detection, it is necessary to maintain a low neutron background as a function of altitude. Initial investigations show the variation in the neutron background can be decreased with the application of a cosmic-ray shield. The results of the studies along with a representative data set are presented.

The neutron resonance phenomena constitute one of the most fundamental subjects in nuclear physics as well as in reactor physics. It is the area where the concepts of nuclear interaction and the treatment of the neutronic balance in reactor lattices become intertwined. The later requires the detailed knowledge of resonance structures of many nuclide of practical interest to the development of nuclear energy. The key issue of the resonance treatment in reactor applications is directly associated with the use of the microscopic cross sections in the macroscopic reactor cells with a wide range of composition, temperature,and geometric configurations. It gives rise to the so called self-shielding effect. The accurate estimations of such a effect is essential not only in the calculation of the criticality of a reactor but also from the point of view of safety considerations. The latter manifests through the Doppler effect particularly crucial to the fast reactor development. The task of accurate treatment of the self-shielding effect, however, is by no means simple. In fact, it is perhaps the most complicated problem in neutronphysics which, strictly speaking, requires the dependence of many physical variables. Two important elements of particular interest are : (1) a concise description of the resonance cross sections as a function of energy and temperature; (2) accurate estimation of the corresponding neutron flux where appropriate. These topics will be discussed from both the historical as well as the state-of-art perspectives.

The beginning of the 21st century was marked by a breakthrough in the studies of thermal radiation of neutron stars. Observations with modern space telescopes have provided a wealth of valuable information. Being correctly interpreted, this information can elucidate physics of superdense matter in the interiors of these stars. The theory of formation of thermal spectra of neutron stars is based on the physics of plasmas and radiative processes in stellar photospheres. It provides the framework for interpretation of observational data and for extracting neutron-star parameters from these data. This paper presents a review of the current state of the theory of surface layers of neutron stars and radiative processes in these layers, with the main focus on the neutron stars that possess strong magnetic fields. In addition to the conventional deep (semi-infinite) atmospheres, radiative condensed surfaces of neutron stars and "thin" (finite) atmospheres are also considered.

The production of polarized neutrons in magnetized iron has been studied, using the intense neutron beams available at the Argonne heavy water pile. The theoretical work of Halpern et al., used as a guide in the experiments, has been checked in many respects, with the exception that the polarization cross section p has a measured value of 3.15 barns compared to the theoretical 1 barn. The application of neutron polarization to the measurement of the approach to saturation in ferromagnets is described and preliminary results are reported.

According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

Part 2 of "Project X: Accelerator Reference Design, Physics Opportunities, Broader Impacts". In this Part, we outline the particle-physics program that can be achieved with Project X, a staged superconducting linac for intensity-frontier particle physics. Topics include neutrino physics, kaon physics, muon physics, electric dipole moments, neutron-antineutron oscillations, new light particles, hadron structure, hadron spectroscopy, and lattice-QCD calculations. Part 1 is available as arXiv:1306.5022 [physics.acc-ph] and Part 3 is available as arXiv:1306.5024 [physics.acc-ph].

Neutron/Proton Capture Neutron/Proton Capture Beam Line 13 Fuels Discovery Fever for Fundamental Physicists Research Contact: Geoff Greene June 2011, Written by Agatha Bardoel Serpil Kucuker Dogan (left) and Matthew Musgrave prepare a helium-3 cooling cell that is used to measure the angle at which the neutron beam strikes the liquid hydrogen sample. The simplest, most sensible " Big Bang" universe, theoretical physicists believe, would be one in which equal numbers of particles and antiparticles are formed in pairs. As the universe cools, most of these particles would encounter their antiparticles, and they would annihilate. "In many ways, the most reasonable universe would be one in which there is no matter," says the University of Tennessee's Dr. Geoff Greene.

It is now widely acknowledged that cosmic rays experiments can test possible new physics directly generated at the Planck scale or at some other fundamental scale. By studying particle properties at energies far beyond the reach of any man-made accelerator, they can yield unique checks of basic principles. A well-known example is provided by possible tests of special relativity at the highest cosmic-ray energies. But other essential ingredients of standard theories can in principle be tested: quantum mechanics, uncertainty principle, energy and momentum conservation, effective space-time dimensions, hamiltonian and lagrangian formalisms, postulates of cosmology, vacuum dynamics and particle propagation, quark and gluon confinement, elementariness of particles... Standard particle physics or string-like patterns may have a composite origin able to manifest itself through specific cosmic-ray signatures. Ultra-high energy cosmic rays, but also cosmic rays at lower energies, are probes of both "conventional" and new Physics. Status, prospects, new ideas, and open questions in the field are discussed. The Post Scriptum shows that several basic features of modern cosmology naturally appear in a SU(2) spinorial description of space-time without any need for matter, relativity or standard gravitation. New possible effects related to the spinorial space-time structure can also be foreseen. Similarly, the existence of spin-1/2 particles can be naturally related to physics beyond Planck scale and to a possible pre-Big Bang era.

Topical surveys on the significance and use of print media prove that the need for print media is growing worldwide. This is indicated by the fact that at the end of the millenium Time Magazine acknowledged the s...

The basic principle of the STM experiment is described in Sect. 2.1. A theoretical basis for the treatment of electron tunneling in STM is given by Bardeens theory [1], which is the preeminent quantitative theor...

Neutron activation analysis is yet another technique in the arsenal of diagnostic methods that physicians can draw on to examine the health of their patients. The University of Washington's school of medicine in Seattle is the first facility in the ...

Neutron reflectometry is a relatively new technique [1,2]. In the last years, it has been extensively used for solving soft matter problems like polymer mixing [3,4] or the structure of liquids at the surface [5,

Based on a physical monism, which holds that the matter and space are classified by not a difference of their kind but a difference of magnitude of their density, I derive the most fundamental equation of motion, which is capable of providing a deeper physical understanding than the known physics. For example, this equation answers to the substantive reason of movement, and Newton's second law, which has been regarded as the definition of force, is derived in a substantive level from this equation. Further, the relativistic energy-mass formula is generalized to include the potential energy term, and the Lorentz force and Maxwell equations are newly derived.

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

...require contributions from fundamental research (from developmental...system for stem cell culture does not exist; however, bioreactor...Stem cell bioprocessing: fundamentals and principles. | In recent...require contributions from fundamental research (from developmental...

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Fundamentals of microfluidic cell culture in controlled microenvironments Edmond W. K. Young@wisc.edu Abstract Microfluidics has the potential to revolutionize the way we approach cell biology research. The dimensions of microfluidic channels are well suited to the physical scale of biological cells

"Dedicated to advancing the understanding of the fundamentalphysics of hypersonic combined cycle. of Mechanical & Aerospace Engineering University of Virginia Charlottesville, VA 434.982.5945 National Center entry, descent and landing. #12;RECENT RESEARCH DEVELOPMENTS ï¿½ Ramjet/Scramjet mode transition is being

Three precise measurements exist on static properties of the muon. These are the g factor, g-2, and the frequency of the 3D-2P transition in mesonic phosphorus. They are combined to obtain the best fit to the fundamental constants of the muon.

Fundamental Catalysis Research in Japan ... Japan is one of the foremost nations in catalysis research. ... Dr. Horiuti responded with information on what he and other Japanese research workers were doing, and subsequently I decided to visit Japan to study catalysis during my sabbatical leave from New York University last spring. ...

Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding how: a.) The Sun generates and releases neutrinos, energy and solar-wind hydrogen and helium; b.) An inhabitable planet formed and life evolved around an ordinary-looking star; c.) Continuous climate change - induced by cyclic changes in gravitational interactions of the Sun's energetic core with planets - has favored survival by adaptation.

Glauber's definition of quantum coherence is used for neutron fields under the assumption that the complete occupation number space is a direct product of Fermi subspaces. As a result, completely coherent microfields are obtained which define a density operator in full analogy to Glauber's P representation of boson fields. For better physical significance, a transformation from the P representation to a momentum representation is performed. It is proved that the second-order coherence function in this representation is equivalent to Wolf's second-order coherence function of a classical Dirac field. Finally, the results of the theory are used to calculate explicitly the second-order coherence function and the coherence time of an ideally collimated neutron beam.

Experiments for the determination of the polarization cross section p of iron with monochromatic and non-monochromatic neutrons are described. The absolute value of p as well as its dependence on the neutron velocity is found to be in good agreement with the recent calculations of Steinberger and Wick and also with other experiments. For a complex neutron spectrum originating from a paraffin moderator p¯ is found to be (2.35±0.1)×10-24 cm2 in agreement with previous investigations. It is shown that the larger value of 3.15×10-24 cm2 found by Hughes, Wallace, and Holtzman must be due to spectral differences. The approach of the magnetization of iron towards saturation is also investigated.

Georg Ehlers Georg Ehlers Lead Instrument Scientist: Cold Neutron Chopper Spectrometer (CNCS), SNS Education PhD in Experimental Condensed Matter Physics, the Hahn Meitner Institut, in Berlin, Germany Description of Research Dr. Ehlers joined the Spallation Neutron Source (SNS) in 2003 as the lead instrument scientist for beam line 5, the Cold Neutron Chopper Spectrometer (CNCS). CNCS is a high-resolution, direct geometry, cold neutron, inelastic multi-chopper spectrometer, designed to make use of neutrons with an energy of <50 meV. Before joining the SNS, Dr. Ehlers worked at the Institute Laue-Langevin (ILL), a leading European neutron research facility situated in Grenoble, France for six years. At the ILL, he was instrument-responsible for the spin-echo spectrometers IN11 and IN15, and established a strong research

NEUTRON LIFETIME EXPERIMENT USING UCN STORAGE IN AN `ACCORDION-LIKE' TRAP BY ASHISH M. DESAI determination of the neutron lifetime has an impact on particle physics and cosmology. We report progress towards a measurement of the neutron lifetime using an accordion-like storage trap. Ultracold neutrons

, topographie de Lang aux neutrons. Abstract. 2014 The physical basis of the scattering of neutrons is discussed. In particular, the energy spectrum of the inelastically scattered neutrons may be determined experimentally. The possibilities of the neutron scattering due to their weak absorption coefficient in matter

The concept of extremely dense matter at supra-nuclear density was first speculated by L. Landau in the beginning of 1930s when neutron was just discovered. A historical review on these issues not only explains the interaction between micro and cosmic physics, but also has profound implications for scientific innovation. It is surely meaningful in realistic physics education to look back to this history. (The review was published in Chinese.)

The writers point out that the postulation of the existence of the "neutron," a combination of an electron and a proton, of small size and low energy would be very useful in explaining a number of atomic and cosmic phenomena. They find that a mathematical treatment based on existing theory leads to indications of such a state but no definite proof.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

...the fundamental operations in a physical system, and then at...embedding/encoding operations that must be identified. First, the system being simulated...fundamental dynamical operation (such as gates...present in the system leads to the requirement...

The BPS Skyrme model has been demonstrated already to provide a physically intriguing and quantitatively reliable description of nuclear matter. Indeed, the model has both the symmetries and the energy-momentum tensor of a perfect fluid, and thus represents a field theoretic realization of the "liquid droplet" model of nuclear matter. In addition, the classical soliton solutions together with some obvious corrections (spin-isospin quantization, Coulomb energy, proton-neutron mass difference) led to an accurate modeling of nuclear binding energies for heavier nuclei. These results lead to the rather obvious proposal to try to describe also neutron stars by the BPS Skyrme model coupled to gravity. We find that the resulting self-gravitating BPS Skyrmions provide an excellent description of neutron stars when the parameter values of the model are extracted from nuclear physics. Specifically, the maximum possible mass of a neutron star before black-hole formation sets in is a few solar masses, the precise value depending on the precise values of the model parameters, and the resulting neutron star radius is of the order of 10 km.

The BPS Skyrme model has been demonstrated already to provide a physically intriguing and quantitatively reliable description of nuclear matter. Indeed, the model has both the symmetries and the energy-momentum tensor of a perfect fluid, and thus represents a field theoretic realization of the "liquid droplet" model of nuclear matter. In addition, the classical soliton solutions together with some obvious corrections (spin-isospin quantization, Coulomb energy, proton-neutron mass difference) provide an accurate modeling of nuclear binding energies for heavier nuclei. These results lead to the rather natural proposal to try to describe also neutron stars by the BPS Skyrme model coupled to gravity. We find that the resulting self-gravitating BPS Skyrmions provide excellent results as well as some new perspectives for the description of bulk properties of neutron stars when the parameter values of the model are extracted from nuclear physics. Specifically, the maximum possible mass of a neutron star before black-hole formation sets in is a few solar masses, the precise value depending on the precise values of the model parameters, and the resulting neutron star radius is of the order of 10 km.

The Green's fundamental solutions for several second order elliptic partial differential equations governing various physical processes are found to be interrelated. These solutions are required for boundary integral equation formulations. Thus a solution for one such process is essentially a solution for several others. This is particularly useful for heterogeneous media where the catalog of existing fundamental solutions is meager. After a discussion of these relationships, a new class of two dimensional fundamental solutions involving axisymmetric material variations is given.

Abstract Delayed neutrons (DN) play an important role in nuclear reactor physics. Innovative critical reactor studies bring to light the need of new DN yields data. For the thorium fuel cycle DN data for 232Th is needed. In the literature, significant discrepancies were observed for energies below 4 MeV and data are dispersed around 14 MeV. Therefore DN absolute yields from 232Th fission have been determined at the PTB Ion Accelerator Facility in Braunschweig. A consistent set of data has been measured for incident neutrons with energies of 2, 3, 4, 6, 7, 10 and 16 MeV.

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

A holographic dual of a finite-temperature SU(N_c) gauge theory with a small number of flavours N_f viscosity to entropy ratio in these theories saturates the conjectured universal bound eta/s >= 1/4\\pi. The contribution of the fundamental matter eta_fund is therefore enhanced at strong 't Hooft coupling lambda; for example, eta_fund ~ lambda N_c N_f T^3 in four dimensions. Other transport coefficients are analogously enhanced. These results hold with or without a baryon number chemical potential.

The fundamental ground tone vibration of H2, HD, and D2 is determined to an accuracy of 2×10-4??cm-1 from Doppler-free laser spectroscopy in the collisionless environment of a molecular beam. This rotationless vibrational splitting is derived from the combination difference between electronic excitation from the X1?g+, v=0, and v=1 levels to a common EF1?g+, v=0 level. Agreement within 1? between the experimental result and a full ab initio calculation provides a stringent test of quantum electrodynamics in a chemically bound system.

Properties of single crystals in particular often differ with different crystal directions as a consequence of constraints imposed by atomic packing and arrangements as well as the placement of substitutional ...

In the presence of a cosmological constant, ordinary Poincare' special relativity is no longer valid and must be replaced by a de Sitter special relativity, in which Minkowski space is replaced by a de Sitter spacetime. In consequence, the ordinary notions of energy and momentum change, and will satisfy a different kinematic relation. Such a theory is a different kind of a doubly special relativity. Since the only difference between the Poincare' and the de Sitter groups is the replacement of translations by certain linear combinations of translations and proper conformal transformations, the net result of this change is ultimately the breakdown of ordinary translational invariance. From the experimental point of view, therefore, a de Sitter special relativity might be probed by looking for possible violations of translational invariance. If we assume the existence of a connection between the energy scale of an experiment and the local value of the cosmological constant, there would be changes in the kinematics of massive particles which could hopefully be detected in high-energy experiments. Furthermore, due to the presence of a horizon, the usual causal structure of spacetime would be significantly modified at the Planck scale.

Solar sails enable a wide range of high- ... system. They are also an enabling propulsion technology for two types of deep-space missions ... and the large-scale gravitational field of the solar system: the first...

of the art thermal spray deposition system for robotically controlled coating of ceramic matrix composites turbine engines operate. Our group is exploring the mechanisms by which current coatings function engineering materials and the processes to make them." Haydn Wadley University Professor and Edgar A. Starke

Fast Proton Hopping in Ice Fast Proton Hopping in Ice Fast Proton Hopping in Ice (Ih) Confirmed by Quasi-Elastic Neutron Scattering "With these results, we have an experimental proof of fast proton hopping in ice," researcher says Research Contact: Alexander Kolesnikov June 2011, Written by Agatha Bardoel Protons (positive hydrogen ions) in an ice lattice have been "seen" to fast hop from one water molecule to another, using quasi-elastic neutron scattering at the SNS Backscattering Spectrometer, BASIS. This fundamental phenomenon that occurs at very low temperatures has important consequences for future investigations of proton conductivity in solids. The research could open the door to a new understanding of how electrolytes work in a system. Proton hopping in ice occurs when "extra" protons diffuse through

The neutron polarization cross section of iron has been measured as a function of energy from 0.7 to 3.3A by two methods: using the single transmission effect in a block of polycrystalline iron at energies selected by a quartz crystal monochromator; and using a single crystal of magnetized magnetite to analyze the beam emerging from the iron polarizer, the magnetite crystal itself serving as monochromator. The measured values are compared with those of other observers and the theoretically expected values. These are found to agree fairly well within the limits of accuracy of the measurements and existing knowledge of the wave function of the iron 3d shell. The two techniques were used also to determine the average polarization (32 percent) as seen by a 1v detector in a beam of reactor neutrons emerging from a 4-cm thick polarizing block of iron. Problems and techniques associated with the measurement of the average polarization of a continuous spectrum are discussed. A simplified experimental treatment of the problem of beam "hardening" is described. A description is given of the use of the magnetic resonance method in conjunction with a single-crystal magnetite analyzer for the measurement of neutron polarization.

We assume that the neutron-neutron potential is well-behaved and velocity-dependent. We can then apply perturbation theory to find the energy per particle of a neutron gas, in the range of Fermi wave numbers 0.5

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Fundamental Study of Single Biomass Particle Combustion Maryam Momeni #12;Fundamental Study of Single Biomass Particle Combustion Maryam Momeni Dissertation submitted to the Faculty of Engineering Fundamental Study of Single Biomass Particle Combustion This thesis is a comprehensive study of single biomass

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objectives of this project were (1) to develop an enhanced fundamental understanding of the coordination chemistry of hazardous-metal-ion complexation with water-soluble metal-binding polymers, and (2) to exploit this knowledge to develop improved separations for analytical methods, metals processing, and waste treatment. We investigated features of water-soluble metal-binding polymers that affect their binding constants and selectivity for selected transition metal ions. We evaluated backbone polymers using light scattering and ultrafiltration techniques to determine the effect of pH and ionic strength on the molecular volume of the polymers. The backbone polymers were incrementally functionalized with a metal-binding ligand. A procedure and analytical method to determine the absolute level of functionalization was developed and the results correlated with the elemental analysis, viscosity, and molecular size.

The sustained interest in the neutron and its use as a probe of the structure and dynamics of condensed matter is examined against the background of neutron availabil-ity. An analysis is made of developments in neutron source brightness, instrument physics and experimental methodology which have been or are likely to be of outstand-ing value in physics, chemistry, biology and materials technology studies. The role of pulsed sources as the next step ahead in neutron source brightness, their need for extensive instrument development to realise this potential and their complementarity with steady-state reactors is analysed using newly available experimental results. This review was received in December 1983.

Neutron scattering measures samples too hot to hold Neutron scattering measures samples too hot to hold Research Contact: Kenneth Kelton August 2013 Liquids and glasses can have unique optical, electronic, and structural applications but are poorly understood compared to crystalline materials, limiting the ability to take advantage of the characteristics of glasses in a range of applications. Containers can react with molten samples at high temperatures or can favor the growth of crystals over the formation of glasses. Using the chemical and isotopic sensitivity of neutron scattering to understand these disordered structures requires a new capability to hold samples in a neutron beam at high temperature without using a solid physical container. New sample environment equipment at Oak Ridge National Laboratory's (ORNL) Spallation Neutron Source (SNS) enables scientists to

Slow neutron scattering provides quantitative information on the structure and dynamics of materials of interest in physics, chemistry, materials science, biology, geology, and other fields. Liquid hydrogen is a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. In particular the rapid drop of the slow neutron scattering cross section of liquid parahydrogen below 14.5~meV is especially interesting and important. We have measured the total cross section and the scattering cross section for slow neutrons with energies between 0.43~meV and 16.1~meV on liquid hydrogen at 15.6~K using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge National Laboratory. At 1~meV this measurement is a factor of 3 below the data from previous work which has been used in the design of liquid hydrogen moderators at slow neutron sources. We describe our measurements, compare them with previous work, and discuss the implications for designing more intense slow neutron sources.

An innovative accelerator-based neutron source for boron neutron capture therapy has started operation at the Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using 7Li(p,n)7Be threshold reaction. In the article, techniques to detect neutron and gamma-rays at the facility are described. Gamma radiation is measured with NaI and BGO gamma-spectrometers. The total yield of neutrons is determined by measuring the 477 keV ?-quanta from beryllium decay. For the rough analysis of the generated neutron spectrum we used bubble detectors. As the epithermal neutrons are of interest for neutron capture therapy the NaI detector is used as activation detector. We plan to use a time-of-flight technique for neutron spectra measurement. To realize this technique a new solution of short time neutron generation is proposed.

The past history, present performance and future prospects for neutron scattering facilities will be discussed. Special features of neutron scattering techniques applicable to biological problems will be ... . Th...

In 2012 the diffraction community will celebrate 100 years since the prediction of X-ray diffraction by M. Laue, and following his suggestion the first beautiful diffraction experiment by W. Friedrich and P. Knipping. The significance of techniques based on the analysis of the diffraction of X-rays, neutrons, electrons and Mossbauer photons discovered later, has continued to increase in the past 100 years. The aim of this symposium is to provide a forum for discussion of using state-of-the-art neutron and X-ray scattering techniques for probing advanced materials. These techniques have been widely used to characterize materials structures across all length scales, from atomic to nano, meso, and macroscopic scales. With the development of sample environments, in-situ experiments, e.g., at temperatures and applied mechanical load, are becoming routine. The development of ultra-brilliant third-generation synchrotron X-ray sources, together with advances in X-ray optics, has created intense X-ray microbeams, which provide the best opportunities for in-depth understanding of mechanical behavior in a broad spectrum of materials. Important applications include ultra-sensitive elemental detection by X-ray fluorescence/absorption and microdiffraction to identify phase and strain with submicrometer spatial resolution. X-ray microdiffraction is a particularly exciting application compared with alternative probes of crystalline structure, orientation and strain. X-ray microdiffraction is non-destructive with good strain resolution, competitive or superior spatial resolution in thick samples, and with the ability to probe below the sample surface. Advances in neutron sources and instrumentation also bring new opportunities in neutron scattering research. In addition to characterizing the structures, neutrons are also a great tool for elucidating the dynamics of materials. Because neutrons are highly penetrating, neutrons have been used to map stress in engineering systems. Neutrons have also played a vital role in our understanding of the magnetism and magnetic properties. Specialized instruments have been built to gain physical insights of the fundamental mechanisms governing phase transformation and mechanical behaviors of materials. The application of those techniques, in combination with theoretical simulations and numerical modeling, will lead to major breakthroughs in materials science in the foreseeable future that will contribute to the development of materials technology and industrial innovation.

A direct neutronneutron scattering length, ann, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of ann will not only help resolve conflicting results of ann by indirect means, but also in comparison to the protonproton scattering length, app, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrumMaxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermalthermal and thermalepithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

Physics Folklore Physics Folklore By Lynne Zielinski &nbsp&nbsp&nbsp&nbsp&nbsp Sometime after World War II physicists began to change their way of giving names to theoretical ideas. Before then, new ideas were given titles such as "special relativity theory" or "neutrons." A precursor of the new kinds of names came in 1953 when Murray Gell-Mann and Kazuhiko Hishijima decided to name one of the properties of subatomic particles "strangeness." Gell-Mann accelerated the trend in 1961 by calling his group-theoretic way of explaining the properties of particles "The Eightfold Way." Gell-Mann's crazy names finally reached the consciousness of the general public in 1964 when he described the particles involved in the next stage of his thinking as "quarks." p. 508, source B

Neutron reflectometry provides a powerful non-destructive analytic technique to measure physical properties of interfacial materials. The sample reflectivity provides information about composition, thickness, and roughness of films with 0.1 nm resolution. The use of neutrons has the additional advantage of being able to label selected atomic species by using different isotopes. Two examples are presented to demonstrate the use of neutron reflectometry in measuring the thermal expansion of a buried thin polymer film and measuring the change in polymer mobility near a solid substrate.

Materials accounting is essential to providing the necessary assurance for verifying the effectiveness of a safeguards system. The use of measurements, analyses, records, and reports to maintain knowledge of the quantities of nuclear material present in a defined area of a facility and the use of physical inventories and materials balances to verify the presence of special nuclear materials are collectively known as materials accounting for nuclear safeguards. This manual, prepared as part of the resource materials for the Safeguards Technology Training Program of the US Department of Energy, addresses fundamental aspects of materials accounting, enriching and complementing them with the first-hand experiences of authors from varied disciplines. The topics range from highly technical subjects to site-specific system designs and policy discussions. This collection of papers is prepared by more than 25 professionals from the nuclear safeguards field. Representing research institutions, industries, and regulatory agencies, the authors create a unique resource for the annual course titled ''Materials Accounting for Nuclear Safeguards,'' which is offered at the Los Alamos National Laboratory.

The neutron lifetime has been measured by counting the neutrons remaining in a fluid-walled bottle as a function of the duration of storage. Losses of neutrons caused by the wall reflections are eliminated by varying the bottle volume-to-surface ratio. The result obtained is ??=887.6±3 s.

There has been a current feeling of dissatisfaction in the physics community concerning the content and direction of introductory physics courses. The presented position is that this unease does not originate from the lack of exotic new physics in introductory courses but rather from the outdated philosophical picture that these courses paint. Research in the area of fundamental interactions has revealed a natural structure that seems to cover all of physics. This structure is centered on a dynamics nested in the space?time of relativity. The four fundamental interactions originate from internal symmetries embedded in these dynamics. This is the paradigm that should be the template of present physics courses. ?

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

The reaction D(n ,2n)p has been measured at Einc=14.1 MeV, ?n (3)=?n(4)=30?, ?=180?, and the results are compared with the predictions of two separable-potential models. Neutron-proton and proton-proton quasifree scattering from nucleon + deuteron reactions at 14 MeV are also compared with the predictions of the same models. The upper limit of 2 mb/sr2 is determined for the reaction D(n,n?)d.

Publication quality results were obtained for several experiments and materials systems including: (i) Patterning and smoothening of sapphire surfaces by energetic Ar+ ions. Grazing Incidence Small Angle X-ray Scattering (GISAXS) experiments were performed in the system at the National Synchrotron Light Source (NSLS) X21 beamline. Ar+ ions in the energy range from 300 eV to 1000 eV were used to produce ripples on the surfaces of single-crystal sapphire. It was found that the ripple wavelength varies strongly with the angle of incidence of the ions, which increase significantly as the angle from normal is varied from 55° to 35°. A smooth region was found for ion incidence less than 35° away from normal incidence. In this region a strong smoothening mechanism with strength proportional to the second derivative of the height of the surface was found to be responsible for the effect. The discovery of this phase transition between stable and unstable regimes as the angle of incidence is varied has also stimulated new work by other groups in the field. (ii) Growth of Ge quantum dots on Si(100) and (111). We discovered the formation of quantum wires on 4° misoriented Si(111) using real-time GISAXS during the deposition of Ge. The results represent the first time-resolved GISAXS study of Ge quantum dot formation. (iii) Sputter deposition of amorphous thin films and multilayers composed of WSi2 and Si. Our in-situ GISAXS experiments reveal fundamental roughening and smoothing phenomena on surfaces during film deposition. The main results of this work is that the WSi2 layers actually become smoother during deposition due to the smoothening effect of energetic particles in the sputter deposition process.

This program was aimed at creating a quantitative physical description, at the micrometer and nanometer levels, of the physical interactions of neutrons with tissue through the ejected secondary charged particles. The authors used theoretical calculations whose input includes neutron cross section data; range, stopping power, ion yield, and straggling information; and geometrical properties. Outputs are initial and slowing-down spectra of charged particles, kerma factors, average values of quality factors, microdosimetric spectra, and integral microdosimetric parameters such as {bar y}{sub F}, {bar y}{sub D}, y{sup *}. Since it has become apparent that nanometer site sizes are also relevant to radiobiological effects, the calculations of event size spectra and their parameters were extended to these smaller diameters. This information is basic to radiological physics, radiation biology, radiation protection of workers, and standards for neutron dose measurement.

With an average density higher than the nuclear density, neutron stars (NS) provide a unique test-ground for nuclear physics, quantum chromodynamics (QCD), and nuclear superfluidity. Determination of the fundamental interactions that govern matter under such extreme conditions is one of the major unsolved problems of modern physics, and -- since it is impossible to replicate these conditions on Earth -- a major scientific motivation for SKA. The most stringent observational constraints come from measurements of NS bulk properties: each model for the microscopic behaviour of matter predicts a specific density-pressure relation (its `Equation of state', EOS). This generates a unique mass-radius relation which predicts a characteristic radius for a large range of masses and a maximum mass above which NS collapse to black holes. It also uniquely predicts other bulk quantities, like maximum spin frequency and moment of inertia. The SKA, in Phase 1 and particularly in Phase 2 will, thanks to the exquisite timing pr...

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

In order to resolve long?standing discrepancies in indirect measurements of the neutron?neutron scattering length ann and contribute to solving the problem of the charge symmetry of the nuclear force the collaboration DIANNA (Direct Investigation of ann Association) plans to measure the neutron?neutron scattering cross section ? nn . The key issue of our approach is the use of the through?channel in the Russia reactor YAGUAR with a peak neutron flux of 1018 /cm2/s. The proposed experimental setup is described. Results of calculations are presented to connect ? nn with the nn?collision detector count rate and the neutron flux density in the reactor channel. Measurements of the thermal neutron fields inside polyethylene converters show excellent prospects for the realization of the direct nn?experiment.

247: Construction and Operation of the Spallation Neutron 247: Construction and Operation of the Spallation Neutron Source EIS-0247: Construction and Operation of the Spallation Neutron Source SUMMARY The United States needs a high-flux, short- pulsed neutron source to provide its scientific and industrial research communities with a much more intense source of pulsed neutrons for neutron scattering research than is currently available. This source would assure the availability of a state-of-the-art neutron research facility in the United States in the decades ahead. This facility would be used to conduct research in areas such as materials science, condensed matter physics, the molecular structure of biological materials, properties of polymers and complex fluids, and magnetism. In addition to creating new scientific and

Monoenergetic neutron reference fields are required for the calibration of neutron detectors and dosemeters for various applications ranging from nuclear physics and nuclear data measurements to radiation protection. In a series of two separate publications the metrological aspects of the production and measurement of fast neutrons are reviewed. In the first part, requirements for the nuclear reactions used to produce neutron fields as well as methods for target characterization and the general layout of reference facilities were discussed. This second part focuses on the most important techniques for field characterization and includes the determination of the neutron fluence as well as the spectral neutron distribution and the determination of the fluence of contaminating photons. The measurements are usually carried out relative to reference cross sections which are reviewed in a separate contribution, but for certain conditions 'absolute' methods for neutron measurements can be used which are directly traceable to the international system of units (SI).

Lighting accounts for approximately 30% of overall electricity use and demand in commercial buildings. This handbook for utility personnel provides a source of basic information on lighting principles, lighting equipment, and other considerations related to lighting design. The handbook is divided into three parts. Part One, Physics of Light, has chapters on light, vision, optics, and photometry. Part Two, Lighting Equipment and Technology, focuses on lamps, luminaires, and lighting controls. Part Three, Lighting Design Decisions, deals with the manner in which lighting design decisions are made and reviews relevant methods and issues. These include the quantity and quality of light needed for visual tasks, calculation methods for verifying that lighting needs are satisfied, lighting economics and methods for evaluating investments in efficient lighting systems, and miscellaneous design issues including energy codes, power quality, photobiology, and disposal of lighting equipment. The handbook contains a discussion of the role of the utility in promoting the use of energy-efficient lighting. The handbook also includes a lighting glossary and a list of references for additional information. This convenient and comprehensive handbook is designed to enable utility lighting personnel to assist their customers in developing high-quality, energy-efficient lighting systems. The handbook is not intended to be an up-to-date reference on lighting products and equipment.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

The yield of delayed neutrons, v{sub d}, from thermal-neutron-induced fission of {sup 245}Cm is measured. Experiments aimed at studying the properties of delayed neutrons from the fission of some reactor isotopes and initiated in 1997 were continued at the upgraded Isomer-M facility by a method according to which a periodic irradiation of a sample with a pulsed neutron beam from the IBR-2 reactor was accompanied by recording emitted neutrons in the intervals between the pulses. The accuracy of the resulting total delayed-neutron yield v{sub d} = (0.64 {+-} 0.02)% is two times higher than that in previous measurements. This work was performed at the Frank Laboratory of NeutronPhysics at the Joint Institute for Nuclear Research (JINR, Dubna).

Review articles are in preparation for the 2003 edition of the CRC's Handbook of Chemistry and Physics dealing with both non-neutron and neutron nuclear data. Highlights include: withdrawal of the claim for discovery of element 118; new measurements of isotopic abundances have led to changes for many elements; a new set of recommended standards for calibration of {gamma}-ray energies have been published for many nuclides; new half-life measurements reported for very short lived isotopes, many long-lived nuclides and {beta}{beta} decay measurements for quasi-stable nuclides; a new reassessment of spontaneous fission (sf) half-lives for ground state nuclides, distinguishing half-lives from sf decay and cluster decay half-lives and the new cluster-fission decay; charged particle cross sections, (n,p) and (n,{alpha}) measurements for thermal neutrons incident on light nuclides; new thermal (n,{gamma}) cross sections and neutron resonance integrals measured. Details are presented.

MSc APPLIED PHYSICS #12;MSc APPLIED PHYSICS This taught Masters course is based on the strong research in Applied Physics in the University's Department of Physics. The department has an impressive photonics and quantum optics, Physics and the Life Sciences, and solid state physics. The knowledge gained

FUNDAMENTALS OF ENGINEERING SUPPLIED-REFERENCE HANDBOOK National Council of Examiners-1-932613-37-7 Printed in the United States of America April 2010 Revised #12;PREFACE The Fundamentals of Engineering (FE NQRZOHGJH FRYHULQJ WKH UHPDLQGHU RI UHTXLUHG GHJUHH FRXUVHZRUN The FE Supplied-Reference Handbook LV WKH RQO

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are collimnated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

A neutron generator was investigated for a neutron source for BNCT. Neutron generators have some obvious advantages over nuclear reactors for this purpose. The neutron source is the reaction D(d,n)3He. Moderation...

At first wall of a fusion power reactor will be subjected to neutrons, charged particles and radiation, leading to neutron irradiation damage, decrease of thickness by physical sputtering, and high heat flux, ...

...The twentieth century saw two fundamental revolutions in physics-relativity...their immense empirical success. Does their instrumental effectiveness...concepts or the sand of unresolved fundamentals? Does measuring a quantum system probe...

The article focuses on the issue of the two definitions of charge, mainly the gauge charge and the effective charge of fundamental particles. Most textbooks on classical electromagnetism and quantum field theory only works with the gauge charges while the concept of the induced charge remains unattended. In this article it has been shown that for intrinsically charged particles both of the charges remain the same but there can be situations where an electrically neutral particle picks up some electrical charge from its plasma surrounding. The physical origin and the scope of application of the induced charge concept has been briefly discussed in the article.

Dr. Michael Agamalian Dr. Michael Agamalian Lead Scientist, Ultra-Small-Angle Neutron Scattering (USANS), SNS Education PhD in Physics, St. Petersburg Nuclear Physics Institute, Russia Description of Research Michael Agamalian and collaborators have made important contributions to the development of the ORNL Bonse-Hart Ultra-Small-Angle Neutron Scattering instrument (USANS). In particular, they adopted the classical X-ray Bonse-Hart technique for neutrons by modifying the Si channel-cut crystal and introducing an additional element, a Cd absorber. This innovation, combined with application of a specialized chemical-mechanical treatment of the diffractive surfaces of the Si channel-cut crystal, has increased the sensitivity of the ORNL USANS instrument by three orders of magnitude. This

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Called the Christmas Burst, GRB 101225A was freakishly lengthy and it produced radiation at unusually varying wavelengths. December 1, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Contact

Relativistic world-line Hamiltonian for strongly interacting 3q systems in magnetic field is derived from the path integral for the corresponding Green's function. The neutral baryon Hamiltonian in magnetic field obeys the pseudomomentum conservation and allows a factorization of the c.m. and internal motion. The resulting expression for the baryon mass in magnetic field is written explicitly with the account of hyperfine, OPE and OGE (color Coulomb) interaction. The neutron mass is fast decreasing with magnetic field, losing 1/2 of its value at eB~0.25 GeV^2 and is nearly zero at eB~0.5 GeV^2. Possible physical consequences of the calculated mass trajectory of the neutron, M_n(B), are presented and discussed.

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

... of its title. It is not for the nuclear physicist, nor even for the neutron physicist, but for the student of solids and liquids. "Thermal ... physicist, but for the student of solids and liquids. "Thermal neutron ...

Neutron activation analysis (NAA) is an that relies on the measurement of ?-rays emitted from a sample that was irradiated by neutrons. The rate at which ?-rays are emitted from an element in a sample is dir...

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Unconventional Superconductors Unconventional Superconductors Doug Scalapino discusses "common thread" linking unconventional superconducting materials Dec 2011, Written by Deborah Counce Douglas Scalapino Professor Emeritus Douglas Scalapino. Douglas Scalapino was the inaugural speaker for a new joint lecture series sponsored by the Spallation Neutron Source and the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory. He is Research Professor of Physics at the University of California-Santa Barbara. A leading theorist in condensed matter physics, he has been a fellow of the American Physical Society and a member of the National Academy Sciences. He has been awarded the John Bardeen Prize for theoretical work in superconductivity and the Julius Lilienfeld Prize for outstanding

Job advertisement Faculty 08 (Physics, Mathematics and Computer Science), Institute of Nuclear and astroparticle physics, nuclear chemistry and precision physics with ultracold neutrons and ion traps. We Physics, has an opening within the framework of the Cluster of Excellence PRISMA for a University

It was pointed out recently that oscillation of the neutron $n$ into mirror neutron $n'$, a sterile twin of the neutron with exactly the same mass, could be a very fast process with the the baryon number violation, even faster than the neutron decay itself. This process is sensitive to the magnetic fields and it could be observed by comparing the neutron lose rates in the UCN storage chambers for different magnetic backgrounds. We calculate the probability of $n-n'$ oscillation in the case when a mirror magnetic field $\\vec{B}'$ is non-zero and show that in this case it can be suppressed or resonantly enhanced by applying the ordinary magnetic field $\\vec{B}$, depending on its strength and on its orientation with respect to $\\vec{B}'$. The recent experimental data, under this hypothesis, still allow the $n-n'$ oscillation time order 1 s or even smaller. Moreover, they indicate that the neutron losses are sensitive to the orientation of the magnetic field. %at about $3\\sigma$ level. If these hints will be confirmed in the future experiments, this would point to the presence of the mirror magnetic field on the Earth of the order of 0.1 G, or some equivalent spin-dependent force of the other origin that makes a difference between the neutron and mirror neutron states.

We study the relation between neutron removal cross section (?-N) and neutron skin thickness for finite neutron-rich nuclei using the statistical abrasion ablation model. Different sizes of neutron skin are obtained by adjusting the diffuseness parameter of neutrons in the Fermi distribution. It is demonstrated that there is a good linear correlation between ?-N and the neutron skin thickness for neutron-rich nuclei. Further analysis suggests that the relative increase of neutron removal cross section could be used as a quantitative measure for neutron skin thickness in neutron-rich nuclei.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Various forms of elastic and electronic wave mechanics are essential to the application ... shall take this opportunity to describe the necessary fundamentals of waves and impart an understanding of...

This chapter reviews the fundamental characteristics and basic applications of the silicon ... provides us with a highly integrated platform for electronicphotonic convergence. For the practical achievement of ....

Charge of proton and neutron? Charge of proton and neutron? Previous Question (Charge of proton and neutron?) Questions and Answers Main Index Next Question (How many times bigger is a proton than an electron?) How many times bigger isa proton than an electron? Why do protons and neutrons stay together in the nucleus? The nucleus of an atom is held together by the strong nuclear force that binds together protons and neutrons. Although the strong nuclear force is the strongest of the four fundamental forces, it acts only over very short - typically nuclear - distances. It binds together the protons and neutrons in the nucleus. It also holds together the quarks that make up those protons and neutrons and the other hadrons. Author: Mac Mestayer, Staff Scientist (Other answers by Mac Mestayer)

XII School of Neutron Scattering (SoNS) XII School of Neutron Scattering (SoNS) "Francesco Paolo Ricci" "Introduction to the theory and techniques of neutron scattering and applications to Cultural Heritage" 30 April - 9 May 2014 A Course within the International School of Solid State Physics ETTORE MAJORANA FOUNDATION AND CENTRE FOR SCIENTIFIC CULTURE, Erice (I) Application deadline: 1 st April 2014 Application is now open for the XII School of Neutron Scattering (SoNS) "Francesco Paolo Ricci": Introduction to the theory and techniques of neutron scattering and applications to Cultural Heritage. The school will be held at the ETTORE MAJORANA FOUNDATION AND CENTRE FOR SCIENTIFIC CULTURE, Erice (Sicily, I) as a specialized course within the International School of Solid State Physics (Director: Giorgio Benedek), between the 30

The neutron warhead decision ... Nuclear war moved a step closer last week with the U.S.'s decision to move ahead with production of so-called neutron warheads for use on short-range missiles and in artillery shells. ... And neutron weapons would be almost as effective on ... ...

Fundamental spin physics has made striking progresses in the last years; new ideas, experiments and data interpretations have been proposed and keep emerging. A review of some of the most important issues in the spin structure of nucleons is made and prospects for the future are discussed.

The development and evaluation of a new approach to neutronbrachytherapy is described. This approach accelerator-based fast neutronbrachytherapy involves the interstitial or intracavity insertion of a narrow evacuated accelerator beam tube such that its tip containing the neutron-producing target is placed in or near the tumor.Tumorirradiation via brachytherapy should result in a reduction in the healthy tissue complication rate observed when poorly collimated and/or low energy external neutron beam are used for treatment. Use of a variable energy accelerator provides an advantage over isotopesources for neutronbrachytherapy in that the neutron beam can be turned on and off and the neutronenergy spectrum varied for different treatment applications. A prototype accelerator-based fast neutronbrachytherapy device 10 cm long and 6 mm outer diameter has been constructed and evaluated in terms of its dosimetric output treatment time and practical feasibility. The prototype device is a tube-in-tube design with cooling water running between the inner and outer tubes to cool a beryllium target located at the tip of the inner tube. Cooling experiments were performed and coupled with Monte Carlo simulations to determine treatment times as a function of heat load for various neutron-producing reactions. Using the 9 Be (d n) 10 B reaction at E d =1.5 MeV 66 RBE-Gy (12 Gy physical dose) can be delivered to the boundary of a 4.5-cm-diam treatment volume in 8 min at a heat load of 130 W. Other reactions offer similar treatment times at somewhat higher bombarding energies and also show higher potential for dose enhancement with the boron-10 neutron capture reaction due to their softer neutron spectra. Dose distributions in a water phantom were measured with the prototype brachytherapy tube using the dual-ion chamber technique for the 9 Be (d n) 10 B reaction at E d =1.5 MeV. The measurements and simulations agree within uncertainties and demonstrate that fast neutrons contribute more than 90% of the dose to the target volume.

The main goal of the present contribution is a pedagogical introduction to the fascinating world of neutron stars by relying on relativistic density functional theory. Density functional theory provides a powerful--and perhaps unique--framework for the calculation of both the properties of finite nuclei and neutron stars. Given the enormous densities that may be reached in the core of neutron stars, it is essential that such theoretical framework incorporates from the outset the basic principles of Lorentz covariance and special relativity. After a brief historical perspective, we present the necessary details required to compute the equation of state of dense, neutron-rich matter. As the equation of state is all that is needed to compute the structure of neutron stars, we discuss how nuclear physics--particularly certain kind of laboratory experiments--can provide significant constrains on the behavior of neutron-rich matter.

Joint Institute for Neutron Sciences Joint Institute for Neutron Sciences SHARE Joint Institute for Neutron Sciences JINS is located on Chestnut Ridge within the 80-acre SNS site, part of Oak Ridge National Laboratory. The Joint Institute for Neutron Sciences (JINS) was founded as a collaborative effort between Oak Ridge National Laboratory (ORNL) and The University of Tennessee to promote the use of neutron scattering in various fields of research. Through worldwide collaborations between researchers of the biological and life sciences, energy sciences, polymer science, condensed matter physics and computational sciences, a synergistic consortium will be created at ORNL to elevate the field of neutron sciences to a new level of efficacy for industry, medicine and frontier research. The goal of JINS is to serve as a gateway for users of the Spallation

A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures.

Spallation Neutron Source Spallation Neutron Source Providing the most intense pulsed neutron beams in the world... Accumulator Ring Commissioning Latest Step for Spallation Neutron Source The Spallation Neutron Source, located at Oak Ridge National Laboratory, has passed another milestone on the way to completion this year--the commissioning of the proton accumulator ring. Brookhaven led the design and construction of the accumulator ring, which will allow an order of magnitude more beam power than any other facility in the world. The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The figure on the right shows a schematic of the accumulator ring and transport beam lines that are being designed and built by Brookhaven

......future developments in physics and in particular develop- ments in gravitational physics. We will examine, therefore...questions in gravitational physics. In particular we discuss...the estimates of the rate of neutron stars mergers...ejecta a rarefaction wave passes and the ejecta cools......

Breakthrough quantum information Breakthrough quantum information science and technology Physics Division's quantum information science and technology capability supports present and future Laboratory missions in cyber-security, sensing, nonproliferation, information science, and materials. Collaborating with researchers throughout Los Alamos and leading institutions in the nation, Physics Division scientists are involved in projects in quantum communications, including quantum key distribution and quantum-enabled security and networking, and in quantum cold-atom physics. Recent fundamental science results include the ability to "paint" potentials that can trap Bose-Einstein condensates into geometric forms, such as the toroidal ring of clusters, the density of which is measured in

With Teragauss magnetic fields, surface gravity sufficiently strong to significantly modify light paths, central densities higher than that of a standard nucleus, and rotation periods of only hundredths of a second, young neutron stars are sites of some of the most extreme physical conditions known in the Universe. They generate magnetic winds with particles that are accelerated to energies in excess of a TeV. These winds form synchrotron-emitting bubbles as the particle stream is eventually decelerated to match the general expansion caused by the explosion that formed the neutron stars. The structure of these pulsar wind nebulae allow us to infer properties of the winds and the pulsating neutron stars themselves. The surfaces of the the stars radiate energy from the rapidly cooling interiors where the physical structure is basically unknown because of our imprecise knowledge of the strong interaction at ultrahigh densities. Here I present a summary of recent measurements that allow us to infer the birth properties of neutron stars and to probe the nature of their winds, the physics of their atmospheres, and the structure of their interiors.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

PHYS 2750, Winter 2014 page 1 of 2 General Physics VI: Modern Physics PHYS 2750 1. What is this course all about? The Golden Age of Physics is often referred to as the the period from the late 1800's up to about the mid 1900's. Physics 2750 is a course which explores many of the fundamental

Page Page Edit with form History Facebook icon Twitter icon Â» Modeling of Geothermal Reservoirs: Fundamental Processes, Computer Simulation and Field Applications Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Modeling of Geothermal Reservoirs: Fundamental Processes, Computer Simulation and Field Applications Abstract This article attempts to critically evaluate the present state of the art of geothermal reservoir simulation. Methodological aspects of geothermal reservoir modeling are briefly reviewed, with special emphasis on flow in fractured media. We then examine some applications of numerical simulation to studies of reservoir dynamics, well test design and analysis, and modeling of specific fields. Tangible impacts of reservoir simulation

* Chemical Dynamics * Chemical Dynamics * Solar Conversion Fundamental Interactions flame photosynthesis icon Chemical Dynamics Work focuses on theoretical and experimental investigation of the thermochemistry, dynamics, and kinetics of chemcial reactions in the gas phase, with a particular emphasis on reactions that are important to understanding combusion. Solar Conversion Work focuses on developing a fundamental understanding of structure-function relationships in biological photosynthesis and establishing principles for the design of biomimetic systems for solar energy conversion. Current funding for this work comes primarily from the Department of Energy Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Divisions. April 2011

The Mathematics Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of mathematics and its application to facility operation. The handbook includes a review of introductory mathematics and the concepts and functional use of algebra, geometry, trigonometry, and calculus. Word problems, equations, calculations, and practical exercises that require the use of each of the mathematical concepts are also presented. This information will provide personnel with a foundation for understanding and performing basic mathematical calculations that are associated with various DOE nuclear facility operations.

Abstract In this work, we report the design configuration and the performance of the hybrid Gas Electron Multiplier (GEM) detector. In order to make the detector sensitive to thermal neutrons, the forward electrode of the GEM has been coated with the enriched boron-10 material, which works as a neutron converter. A total of 5×5 cm2 configuration of GEM has been used for thermal neutron studies. The response of the detector has been estimated via using GEANT4 MC code with two different physics lists. Using the QGSP_BIC_HP physics list, the neutron detection efficiency was determined to be about 3%, while with QGSP_BERT_HP physics list the efficiency was around 2.5%, at the incident thermal neutron energies of 25 meV. The higher response of the detector proves that GEM-coated with boron converter improves the efficiency for thermal neutrons detection.

The new cold neutron research facility has been routinely operated at the Budapest Neutron Centre (BNC) since February 2001. This ... of equipment consists of a liquid hydrogen cold neutron source, an optimised s...

A neutron noise-based experiment performed in the TRIGA reactor of the ENEA-Casaccia centre in Italy is presented. This experiment is part of the first phase of the international TRADE programme that seeks a global demonstration of an accelerator-driven system at power. The main objective of that first experimental phase is the measurement at zero-power of fundamentalneutronic parameters. The present experiment performed in the reference critical core configuration has first of all aimed at the inference of the prompt neutron decay constant at critical, which is equal to the ratio of the delayed neutron fraction to the neutron generation time. The neutron-noise technique that has been applied is the power spectral density technique, based on the use of fission chambers operated in fluctuation mode. Two fission chambers, each with a sensitivity of 10-1 cps/nv, have been placed within the core region close to the reflector. The prompt neutron decay constant at delayed critical has been estimated at 132 Â± 2 s-1 with 68% confidence level.

Radio Astronomy Fundamentals I John Simonetti Spring 2012 Radio astronomy provides a very different view of the universe than optical astronomy. Radio astronomers and optical astronomers use astronomy. Radio astronomers talk about sources of radio emission. Cas A is a strong source, for example

We present fundamentals of a prequantum model with hidden variables of the classical field type. In some sense this is the comeback of classical wave mechanics. Our approach also can be considered as incorporation of quantum mechanics into classical signal theory. All quantum averages (including correlations of entangled systems) can be represented as classical signal averages and correlations.

Abstract In this appendix, we present an updated table of neutron scattering lengths and cross sections for most of the known nuclides, based on preexisting works. We include the coherent and incoherent scattering lengths, as well as the spin-dependent scattering lengths b+ and b?, in cases where this information is available. Also presented are the scattering coherent, incoherent, total, and absorption cross sections. We present an overview of the fundamental theory of the magnitudes to which the table is referred, and also a summary of the main experimental techniques used in determining these magnitudes.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Predicting neutron production from cosmic-ray muons Y.-F. Wang, V. Balic, and G. Gratta Physics, Milano, Italy Received 26 January 2001; published 5 June 2001 Fast neutrons from cosmic-ray muons hampered by the difficulty of measuring and calculating neutron production with sufficient accuracy. Indeed

Industry banner Industry banner Neutron scattering research has applications in practically every field, and neutron research at ORNL is leading to productive partnerships with the industrial and business communities. We welcome proposals for all types of research, including those involving proprietary work. Recent studies have led to discoveries with potential applications in fields such as medicine, energy, and various metals technologies. For more information, please see our recent research highlights. Research Collaborations Industry-Driven Research Benefits Plastics Manufacturing Corning uses VULCAN to test limits of ceramic material for car emission controls, filtration devices Neutrons Probe Inner Workings of Batteries Industry and Neutron Science: Working To Make a Match

Experiments on scattering of low-energy neutrons by heavy elements may give information concerning the electric polarizability of the neutron. The relation of the electric polarizability to the low-energy neutron scattering data is developed. One pertinent experiment is discussed and from this an upper bound on the polarizability is obtained. This upper bound to the polarizability ? is an order of magnitude larger than the meson-theoretic estimate of ?. If the value of ? is as small as is predicted by meson theory, or by an analysis of the pion photoproduction data, then it is unlikely to be observed in neutron scattering experiments of the presently achievable accuracy.

Chemical and Engineering Materials Chemical and Engineering Materials SHARE Chemical and Engineering Materials Neutron-based research at SNS and HFIR in Chemical and Engineering Materials strives to understand the structure and dynamics of chemical systems and novel engineering materials. The user community takes advantage of capabilities of neutron scattering for measurements over wide ranges of experimental and operating conditions, including studies of chemical and physical changes in situ. User experiments with diffraction, small-angle scattering, inelastic and quasi-elastic scattering, and neutron imaging instruments address a range of problems in chemistry and in engineering materials research. Current areas of research supported within Chemical and Engineering Materials include: The structure and dynamics of electrical energy storage materials

Paradoxes are a relatively frequent occurrence in physics. The nature of their genesis is diverse and they are found in all branches of physics. There are a number of general and special classifications of paradoxes, but there are no classifications of paradoxes in physics. Nowadays, physics is a fundamental and rather formalized science, the paradoxes of which imply falsity and imprecision. One of the basic methods of addressing a problem is to present classifications that facilitate its formulation and study. This work groups together the paradoxes in physics according to certain common characteristics, which should assist in explaining the causes for paradox formation.

Starting with basic properties of the neutron, this chapter reviews the most important neutron scattering methods that provide valuable information for a ... wide, from standard methods of crystallography to neutron

The scattering of slow neutron beams provides unique, non-destructive, quantitative information on the structure and dynamics of materials of interest in physics, chemistry, materials science, biology, geology, and other fields. Liquid hydrogen is a widely-used neutron moderator medium, and an accurate knowledge of its slow neutron cross section is essential for the design and optimization of intense slow neutron sources. In particular the rapid drop of the slow neutron scattering cross section of liquid parahydrogen below 15 meV, which renders the moderator volume transparent to the neutron energies of most interest for scattering studies, is therefore especially interesting and important. We have placed an upper bound on the total cross section and the scattering cross section for slow neutrons with energies between 0.43 meV and 16.1 meV on liquid hydrogen at 15.6 K using neutron transmission measurements on the hydrogen target of the NPDGamma collaboration at the Spallation Neutron Source at Oak Ridge Nati...

1 PHYSICS (Div. III) Chair: Professor KEVIN JONES Professors: AALBERTS, S. BOLTON*, K. JONES a laser work? What is a black hole? What are the fundamental building blocks of the universe? Physics majors and Astrophysics majors study these and related questions to understand the physical world around

Topaz Guide Bender Topaz Guide Bender Neutron Diffraction @ TOPAZ Workshop on Single Crystal Neutron Diffraction picture 2 September 29 - October 1, 2011 * Spallation Neutron Source * Oak Ridge National Laboratory * Oak Ridge TN, USA TOPAZ 2011 Home Contacts Agenda and Important Deadlines Registration and Payment filler Workshop summary and purpose A workshop on single crystal neutron diffraction will be held at the Spallation Neutron Source at the Oak Ridge National Laboratory (ORNL). It will present invited and contributed talks to showcase cutting edge science and examples where neutron diffraction can make significant contributions; and provide training in neutron structure analysis and sample screening for the preparation of instrument beam-time proposals. TOPAZ is a high resolution wavelength-resolved Laue diffractometer with a versatile sample environment. Commissioning user experiments have demonstrated successfully the instrument capability for structural study of a vitamin B12 derivative, ion distribution in Li-ion battery materials, order and disorder in shape memory intermetallics, magnetic phase transition in multiferroic single crystal and functional thin films. The workshop is directed towards experienced neutron diffraction users and new users alike and encourages members to highlight their research and interest in structure analysis and investigation. The workshop will give opportunity to bring your own single crystal and screen sample quality and scattering power on TOPAZ @ room temperature, to evaluate data collection time and quality for an anticipated experiment. Finally, an opportunity to compose a proposal for neutron beam time (http://neutrons.ornl.gov/users/proposals.shtml) with staff will be provided in the framework of the workshop. The workshop format is well suited for researchers to contribute by showcasing their research and bring their research group or graduate student, who would like to test a single crystal sample. User access training for the ORNL neutron scattering facility will be included. It will be valid for future experiments.

The GERmanium Detector Array, GERDA, is designed for the search for ``neutrinoless double beta decay'' (0-nu-2-beta) with germanium detectors enriched in Ge76. An 18-fold segmented prototype detector for GERDA Phase II was exposed to an AmBe neutron source to improve the understanding of neutron induced backgrounds. Neutron interactions with the germanium isotopes themselves and in the surrounding materials were studied. Segment information is used to identify neutron induced peaks in the recorded energy spectra. The Geant4 based simulation package MaGe is used to simulate the experiment. Though many photon peaks from germanium isotopes excited by neutrons are correctly described by Geant4, some physics processes were identified as being incorrectly treated or even missing.

Neutron activation experiments in radiochemistry ... Describes experimentation involving the neutron activation of a variety of samples irradiated in a subcritical reactor and a paraffin-moderated source. ...

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Specular neutron reflectometry provides a depth profile of the scattering ... material. To date, numerous productive applications of neutron reflectometry have been demonstrated. With the new development ... stil...

Neutron Science Center capacity boost Neutron Science Center capacity boost Los Alamos Neutron Science Center gets capacity boost The facility can simulate the effects of hundreds or thousands of years of cosmic-ray-induced neutrons in a single hour. December 2, 2010 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Contact

We provide a brief review of the physical processes behind the radiative driving of the winds of OB stars and the Bondi-Hoyle-Lyttleton capture and accretion of a fraction of the stellar wind by a compact object, typically a neutron star, in detached high-mass X-ray binaries (HMXBs). In addition, we describe a program to develop global models of the radiatively-driven photoionized winds and accretion flows of HMXBs, with particular attention to the prototypical system Vela X-1. The models combine XSTAR photoionization calculations, HULLAC emission models appropriate to X-ray photoionized plasmas, improved models of the radiative driving of photoionized winds, FLASH time-dependent adaptive-mesh hydrodynamics calculations, and Monte Carlo radiation transport. We present two- and three-dimensional maps of the density, temperature, velocity, ionization parameter, and emissivity distributions of representative X-ray emission lines, as well as synthetic global Monte Carlo X-ray spectra. Such models help to better constrain the properties of the winds of HMXBs, which bear on such fundamental questions as the long-term evolution of these binaries and the chemical enrichment of the interstellar medium.

A conception of Neutron Science Research Project (NSRP) has been proposed in Japan Atomic Energy Research Institute (JAERI) since 1994 for its future big science project. The project aims at exploring new basic science and nuclear energy science by using a high-intensity proton accelerator. NSRP is a complex composed of a powerful superconducting proton linac the target systems which convert the proton beam to neutrons or other particles and the facilities for scientific research programs. The proton linac is required to supply a high-intensity proton beam with an energy up to 1.5 GeV and an average current around 10 mA. The scientific research programs are as follows: In the area of basic science structural biology and material science with slow neutron scattering method neutron nuclear physics and spallation radioisotope physics and in the area of nuclear energy science the experimental feasibility studies of incineration for the nuclear waste transmutation and material developments with a neutron irradiation facility. Other scientific research programs are also proposed such as meson science for meson and muon physics radioisotope production for medical use. Research and development (R&D) have been carried out for the components of the injector system of the proton linac; an ion source an RFQ linac and a part of DTL linac. The conceptual design work and R&D activities for NSRP have started in the fiscal year 1996. The first beam of 1.5 GeV and 1 mA is expected to be extracted from the proton linac by 2004 and finally a 10 mA is to be obtained in 2007 by reflecting the results of technological developments.

The goal of this report was to provide a conceptual plan for a research program that would provide a basis for determining more precisely the biological effectiveness of neutron radiation with emphasis on endpoints relevant to the protection of human health. This report presents the findings of the experts for seven particular categories of scientific information on neutron biological effectiveness. Chapter 2 examines the radiobiological mechanisms underlying the assumptions used to estimate human risk from neutrons and other radiations. Chapter 3 discusses the qualitative and quantitative models used to organize and evaluate experimental observations and to provide extrapolations where direct observations cannot be made. Chapter 4 discusses the physical principles governing the interaction of radiation with biological systems and the importance of accurate dosimetry in evaluating radiation risk and reducing the uncertainty in the biological data. Chapter 5 deals with the chemical and molecular changes underlying cellular responses and the LET dependence of these changes. Chapter 6, in turn, discusses those cellular and genetic changes which lead to mutation or neoplastic transformation. Chapters 7 and 8 examine deterministic and stochastic effects, respectively, and the data required for the prediction of such effects at different organizational levels and for the extrapolation from experimental results in animals to risks for man. Gaps and uncertainties in this data are examined relative to data required for establishing radiation protection standards for neutrons and procedures for the effective and safe use of neutron and other high-LET radiation therapy.

... . Only those elements which have a high thermal-neutron capture cross-section, such as boron-10, lithium-6, and uranium-235, are useful. This suggestion was first put forward ... was first put forward in 1936 by Locher. The utilization of thermal neutron capture by boron-10 for the treatment of human-brain tumours, chiefly glioblastoma multiforme, has been under investigation ...

In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

......shut down. A recent development for a thermal neutron calibration field is a neutron guide used at the research reactor GKSS Geesthacht(35). The result is a high-intensity thermal beam providing a flux of up to 106 s1 with a field size of about 2.5 2......

6 6 Notes: One can use a simple model to deal with price/fundamental relationships. This one predicts monthly average WTI price as a function of OECD total petroleum stock deviations from the normal levels. The graph shows the model as it begins predicting prices in 1992. It shows how well the model has predicted not only the direction, but the magnitude of prices over this 8+ year period. While the model is simple and not perfect, it does predict the overall trends and, in particular, the recent rise in prices. It also shows that prices may have over-shot the fundamental balance for a while -- at least partially due to speculative concerns over Mideast tensions, winter supply adequacy, and Iraq's export policies. Prices moved lower in December, and even undershot briefly the

Bioenergy Bioenergy SHARE Fundamental and Applied Bioenergy Steven Brown (left) and Shihui Yang have developed a microbial strain with an improved ability to convert wood products to biofuel as part of research within the DOE BioEnergy Science Center.Source: ORNL News article ORNL researchers are investigating the biological mechanisms underlying production of biofuels so that those mechanisms can be improved and used to develop a new generation of efficient bioenergy strategies that will reduce U.S. dependence on foreign oil and help curb carbon emissions. Fundamental and applied bioenergy research at ORNL includes studies conducted within the BioEnergy Science Center and the following research areas: Bioconversion Science and Technology Plant-Microbe Interfaces

Over the last few years there has been a great increase in our knowledge of neutron-rich nuclei resulting from the use of large {gamma}-ray arrays to investigate prompt {gamma} rays from fission and deep inelastic reactions. In this paper we shall discuss various aspects of the physics underling the fission and deep-inelastic reaction mechanisms that are relevant to the spectroscopic investigation of neutron-rich nuclei.

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

and energy at the most fundamental level. This includes particle physics experiments, theoretical research and development projects by outside committees of peers appointed by DOE or the University of Chicago as well

The Mechanical Science Handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of mechanical components and mechanical science. The handbook includes information diesel engines, heat exchangers, pumps, valves, and miscellaneous mechanical components. This information will provide personnel with a foundation for understanding the construction and operation of mechanical components that are associated with various DOE nuclear facility operations and maintenance.

The Mechanical Science Handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of mechanical components and mechanical science. The handbook includes information on diesel engines, heat exchangers, pumps, valves, and miscellaneous mechanical components. This information will provide personnel with a foundation for understanding the construction and operation of mechanical components that are associated with various DOE nuclear facility operations and maintenance.

Software Software A new portal for neutron scattering has just been established at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for archival purposes but no new content will be added. We encourage everyone interested in neutron scattering to take full advantage of this exciting new resource for our community. Neutronsources.org Data Formats NeXus: Neutron and X-ray Data Format Crystallographic Binary Format (CBF/imgCIF) Hierarchical Data Format (HDF) Data Analysis and Visualization Data Analysis for Neutron Scattering Experiments (DANSE): distributed data analysis project Large Array Manipulation Program (LAMP): IDL-based data analysis and visualization

The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

In an earlier paper, the contribution of the meson current to the electromagnetic structure of the nucleon was calculated by use of the dispersion relations for pion-nucleon scattering. Here the contribution of the nucleon current to the electromagnetic structure of the neutron is obtained analogously by use of the dispersion relations for neutron-proton scattering. Only the contribution from the one-pion and two-pion states of nucleon-nucleon scattering is considered. It is found that both states reduce the neutron-electron potential, i.e., leads to a smaller charge radius of the neutron. The contribution from the deuteron state is shown to be negligible. The resulting mean-square radii of the neutron, including the contributions of both meson and nucleon current, are (0.23×10-13cm)2 for the charge distribution and (0.41×10-13cm)2 for the magnetic moment distribution with f2=0.08.

Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

The objective of this project is to determine the feasibility of calculating the fast neutron flux in the pressure vessel of a pressurized water reactor by Monte Carlo methods. Neutron reactions reduce the ductility of the steel and thus limit the useful life of this important reactor component. This work was performed for Virginia Power (VEPCO). VIM is a continuous-energy Monte Carlo code which provides a versatile geometrical capability and a neutronphysics data base closely representing the EDNF/B-IV data from which it was derived.

The wavelengths and energies of thermal and cold neutrons are ideally matched to the length and energy scales in the materials that underpin technologies of the present and future: ranging from semiconductors to magnetic devices, composites to biomaterials and polymers. The Spallation Neutron Source (SNS) will use an accelerator to produce the most intense beams of neutrons in the world when it is complete at the end of 2005. The project is being built by a collaboration of six U.S. Department of Energy laboratories. It will serve a diverse community of users drawn from academia, industry, and government labs with interests in condensed matter physics, chemistry, engineering materials, biology, and beyond.

Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

Argonne National Laboratory (ANL) of USA and Kharkov Inst. of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of an experimental neutron source facility. It is an accelerator driven system (ADS) utilizing a subcritical assembly driven by electron accelerator. The facility will be utilized for performing basic and applied nuclear researches, producing medical isotopes, and training young nuclear specialists. Monte Carlo code MCNPX has been utilized as a design tool due to its capability to transport electrons, photons, and neutrons at high energies. However the facility shielding calculations with MCNPX need enormous computational resources and the small neutron yield per electron makes sampling difficulty for the Monte Carlo calculations. A method, based on generating and utilizing neutron source file, was proposed and tested. This method reduces significantly the required computer resources and improves the statistics of the calculated neutron dose outside the shield boundary. However the statistical errors introduced by generating the neutron source were not directly represented in the results, questioning the validity of this methodology, because an insufficiently sampled neutron source can cause error on the calculated neutron dose. This paper presents a procedure for the validation of the generated neutron source file. The impact of neutron source statistic on the neutron dose is examined by calculating the neutron dose as a function of the number of electron particles used for generating the neutron source files. When the value of the calculated neutron dose converges, it means the neutron source has scored sufficient records and statistic does not have apparent impact on the calculated neutron dose. In this way, the validity of neutron source and the shield analyses could be verified. (authors)

Anchoring low-energy nuclear physics to the fundamental theory of strong interactions remains an outstanding challenge. I review the current progress and challenges of the endeavor to use lattice QCD to bridge this connection. This is a particularly exciting time for this line of research as demonstrated by the spike in the number of different collaborative efforts focussed on this problem and presented at this conference. I first digress and discuss the 2013 Ken Wilson Award.

. ' ' The determination of 7, 11, 12 neutron energies by time-of-flight techniques fundamentally consists of measuring the elapsed time between production of a neutron in the target and i, ts arrival at the detector location. The straight line distance the neutron... through the collimator, and 2. 73 m from the collimator exit to the detector. 2 2 4 Measurements Neutron energy spectra were measured both on and off the central beam axis using different radiation field sizes A straight bore research collimator...

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

Using the Dirac-Brueckner-Hartree-Fock approach, the properties of neutron-star matter including hyperons are investigated. In the calculation, we consider both time and space components of the vector self-energies of baryons as well as the scalar ones. Furthermore, the effect of negative-energy states of baryons is partly taken into account. We obtain the maximum neutron-star mass of $2.08\\,M_{\\odot}$, which is consistent with the recently observed, massive neutron stars. We discuss a universal, repulsive three-body force for hyperons in matter.

...temporally directed, it also does not appear anywhere in the fundamental laws of physics. 8 Relatedly...Russell observed causation does not explicitly occur in the fundamental dynamical laws. But of course this does not mean, contra Russell's...

Isolated neutron stars show a diversity in timing and spectral properties, which has historically led to a classification in different sub-classes. The magnetic field plays a key role in many aspects of the neutron star phenomenology: it regulates the braking torque responsible for their timing properties and, for magnetars, it provides the energy budget for the outburst activity and high quiescent luminosities (usually well above the rotational energy budget). We aim at unifying this observational variety by linking the results of the state-of-the-art 2D magneto-thermal simulations with observational data. The comparison between theory and observations allows to place two strong constraints on the physical properties of the inner crust. First, strong electrical currents must circulate in the crust, rather than in the star core. Second, the innermost part of the crust must be highly resistive, which is in principle in agreement with the presence of a novel phase of matter so-called nuclear pasta phase.

Motivated by the possible existence of other universes, with possible variations in the laws of physics, this paper explores the parameter space of fundamental constants that allows for the existence of stars. To make this problem tractable, we develop a semi-analytical stellar structure model that allows for physical understanding of these stars with unconventional parameters, as well as a means to survey the relevant parameter space. In this work, the most important quantities that determine stellar properties-and are allowed to vary-are the gravitational constant G, the fine structure constant {alpha} and a composite parameter C that determines nuclear reaction rates. Working within this model, we delineate the portion of parameter space that allows for the existence of stars. Our main finding is that a sizable fraction of the parameter space (roughly one-fourth) provides the values necessary for stellar objects to operate through sustained nuclear fusion. As a result, the set of parameters necessary to support stars are not particularly rare. In addition, we briefly consider the possibility that unconventional stars (e.g. black holes, dark matter stars) play the role filled by stars in our universe and constrain the allowed parameter space.

We apply the generalized second law of thermodynamics and derive upper limits on the variation in the fundamental constants. The maximum variation in the electronic charge permitted for black holes accreting and emitting in the present cosmic microwave background corresponds to a variation in the fine-structure constant of {delta}{alpha}/{alpha}{approx_equal}2x10{sup -23} per second. This value matches the variation measured by Webb et al. [Phys. Rev. Lett. 82, 884 (1999); Phys. Rev. Lett. 87, 091301 (2001)] using absorption lines in the spectra of distant quasars and suggests the variation mechanism may be a coupling between the electron and the cosmic photon background.

A time-of-flight spectrometer of neutrons in the energy range (0.05 -- 2.5)$\\mu$eV is described. This spectrometer has been tested my measuring the total and differential neutron cross sections for a number of materials: Al, Cu, $^{6}$LiF, Si, Zr, teflon, polyethylene and liquid fluoropolymers, that are essential for experiments in the physics of ultracold neutrons.

Globally neutral neutron stars, obtained from the solution of the called Einstein-Maxwell-Thomas-Fermi equations that account for all the fundamental interactions, have been recently introduced. These configurations have a more general character than the ones obtained with the traditional Tolman-Oppenheimer-Volkoff, which impose the condition of local charge neutrality. The resulting configurations have a less massive and thinner crust, leading to a new mass-radius relation. Signatures of this new structure of the neutron star on the thermal evolution might be a potential test for this theory. We compute the cooling curves by integrating numerically the energy balance and transport equations in general relativity, for globally neutral neutron stars with crusts of different masses and sizes, according to this theory for different core-crust transition interfaces. We compare and contrast our study with known results for local charge neutrality. We found a new behavior for the relaxation time, depending upon the...

Our current understanding of the Universe depends on the interplay of several distinct "matter" components, which interact mainly through gravity, and electromagnetic radiation. The nature of the different components, and possible interactions, tends to be based on the notion of coupled perfect fluids (or scalar fields). This approach is somewhat naive, especially if one wants to be able to consider issues involving heat flow, dissipative mechanisms, or Bose-Einstein condensation of dark matter. We argue that a more natural starting point would be the multi-purpose variational relativistic multi-fluid system that has so far mainly been applied to neutron star astrophysics. As an illustration of the fundamental principles involved, we develop the formalism for determining the non-linear cosmological solutions to the Einstein equations for a general relativistic two-fluid model for a coupled system of matter (non-zero rest mass) and "radiation" (zero rest mass). The two fluids are allowed to interpenetrate and exhibit a relative flow with respect to each other, implying, in general, an anisotropic Universe. We use initial conditions such that the massless fluid flux dominates early on so that the situation is effectively that of a single fluid and one has the usual Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime. We find that there is a Bianchi I transition epoch out of which the matter flux dominates. The situation is then effectively that of a single fluid and the spacetime evolves towards the FLRW form. Such a transition opens up the possibility of imprinting observable consequences at the specific scale corresponding to the transition time.

The total cross sections of the radiative neutron capture processes on 9Be, 14C, 14N, 15N, and 16O are described in the framework of the modified potential cluster model with the classification of orbital states according to Young tableaux. The continued interest in the study of these reactions is due, on the one hand, to the important role played by this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, to the wide use of the capture cross section data in the various applications of nuclear physics and nuclear astrophysics, and, also, to the importance of the analysis of primordial nucleosynthesis in the Universe. This article is devoted to the description of results for the processes of the radiative neutron capture on certain light atomic nuclei at thermal and astrophysical energies. The considered capture reactions are not part of stellar thermonuclear cycles, but involve in the reaction chains of inhomogeneous Big Bang models.

The continued interest to the study of the radiative neutron capture on atomic nuclei is caused, on the one hand, by the important role of this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, by the wide use of the capture cross section data in the various applications of nuclear physics and nuclear astrophysics, and, also, by the analysis of the processes of primordial nucleosynthesis in the Universe. This review is devoted to description of the results obtained for the processes of the radiative neutron capture at thermal and astrophysical energies on certain light atomic nuclei. The consideration of these processes is done in the frame of the potential cluster model, the general principles of which and calculation methods were described earlier. The methods of usage of the obtained on the basis of the phase shift analysis intercluster potentials will be directly demonstrated for calculations of the radiative capture characteristics. The considered capture reactions are not a part of stellar thermonuclear cycles, but they get in the basic reaction chain of primordial nucleosynthesis, taken place in the time of the Universe formation.

The nature and scope of powder diffraction with a white, pulsed beam of neutrons is discussed. Analysis of the data by the Rietveld profile technique is described in brief, and a range of applications in solid...

Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

...conducted at Chalk River (Canada), Geesthacht (Germany), LLB (France) and NIST...deformed limestone that was measured at Geesthacht with this method. It is also possible...with monochromatic neutrons at GKSS, Geesthacht. Equal area projection, linear contours...

Confronting theoretical models with observations of thermal radiation emitted by neutron stars is one of the most important ways to understand the properties of both, superdense matter in the interiors of the neutron stars and dense magnetized plasmas in their outer layers. Here we review the theory of thermal emission from the surface layers of strongly magnetized neutron stars, and the main properties of the observational data. In particular, we focus on the nearby sources for which a clear thermal component has been detected, without being contaminated by other emission processes (magnetosphere, accretion, nebulae). We also discuss the applications of the modern theoretical models of the formation of spectra of strongly magnetized neutron stars to the observed thermally emitting objects.

Physics Division activities in standoff active-interrogation for detecting Physics Division activities in standoff active-interrogation for detecting terrorist nuclear devices, 2011 Detonation of a terrorist nuclear device in a major city would have severe economic, psychological and cultural consequences. To help prevent the fulfillment of such a threat, Physics Division has been exploring techniques by which highly-enriched uranium could be detected before reaching its intended target. We have focused on the use of high-energy protons and negative-muons because of their ability to probe deeply into structures and shielding that would surround the uranium, and their capability to stimulate radiation signatures indicating 235U. Our experimental studies for standoff active-interrogation are enabled by the 800-MeV proton beam at the Los Alamos Neutron Science Center, which

Sample records for fundamental neutron physics from the National Library of Energy Beta (NLEBeta)

Note: This page contains sample records for the topic "fundamental neutron physics" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.

It is shown that the observation of the spectra of leading neutrons from proton beams can be a good probe of absorptive and migration effects. We quantify how these effects modify the Reggeized pion-exchange description of the measurements of leading neutrons at HERA. We are able to obtain a satisfactory description of all the features of these data. We also briefly discuss the corresponding data for leading baryons produced in hadron-hadron collisions.

......Neutron Spectrometry and Dosimetry in Specific Locations at Two CANDU Power Plants J.C. Nunes A.J. Waker A. Arneja Neutron...in locations of interest to the health physics staff at two CANDU power plants in Ontario, Canada. Spectrometry and dosimetry......

...holds but equation (17) does not, does the central site protect...apply: 764 Ch. Hauert Fundamental clusters in spatial 2...note that the reverse does not necessarily hold...powerful approximations to fundamental clusters. 3. CLUSTER...

The root-mean-square radius for neutrons in nuclei is investigated in the Skyrme Hartree-Fock model. The main source of theoretical variation comes from the exchange part of the density-dependent interaction which can be related to a basic property of the neutron equation of state. A precise measurement of the neutron radius in 208Pb would place an important new constraint on the equation of state for neutron matter. The Friedman-Pandharipande neutron equation of state would lead to a very precise value of 0.16±0.02 fm for the difference between the neutron and the proton root-mean-square radius in 208Pb.

A perspective on fundamental parameters and precision tests of the Standard Model is given. Weak neutral current reactions are discussed with emphasis on those processes involving (polarized) electrons. The role of electroweak radiative corrections in determining the top quark mass and probing for ``new physics`` is described.

We have developed tools for the preparation of coupled multigroup proton/neutron cross section libraries. Our method is to use NJOY to process evaluated nuclear data files for incident particles below 150 MeV and MCNPX to produce data for higher energies. We modified the XSEX3 program of the MCNPX code system to produce Legendre expansions of scattering matrices generated by sampling the physics models that are comparable to the output of the GROUPR routine of NJOY. Our code combines the low and high energy scattering data with user input stopping powers and energy deposition cross sections that we also calculated using MCNPX. Our code also calculates momentum transfer coefficients for the library and optionally applies an energy straggling model to the scattering cross sections and stopping powers. The motivation was initially for deterministic solution of space radiation shielding calculations using Attila, but noting that proton therapy treatment planning may neglect secondary neutron dose assessments because of difficulty and expense, we have also investigated the feasibility of multi group methods for this application. We have shown that multigroup MCNPX solutions for secondary neutron dose compare well with continuous energy solutions and are obtainable with less than half computational cost. This efficiency comparison neglects the cost of preparing the library data, but this becomes negligible when distributed over many multi group calculations. Our deterministic calculations illustrate recognized obstacles that may have to be overcome before discrete ordinates methods can be efficient alternatives for proton therapy neutron dose calculations.

...D) has one and only one fundamental solution E(R(D)) with...Here, we suppose that R pr does not contain multiple factors...D) has one and only one fundamental matrix , i.e. P(D)E...system P ad(D) and the fundamental solution E(Q(D)) of...

...Here we have identified a fundamental food web motif, a generalist...structures, it remains that the fundamental unit underlying this hierarchical...motif we studied here, it does importantly suggest that our...Representative food web showing the fundamental food web module of a generalist...

By using fundamental units c, h, G as conversion factors one can easily transform the dimensions of all observables. In particular one can make them all ``geometrical'', or dimensionless. However this has no impact on the fact that there are three fundamental units, G being one of them. Only experiment can tell us whether G is basically fundamental.

Fundamentals of Biomass Pretreatment by Fractionation Poulomi Sannigrahi 1,2 and Arthur J. Ragauskas 1,2,3 1 BioEnergy Science Center, Oak Ridge, USA 2 Institute of Paper Science and Technology, Georgia Institute of Technology, Atlanta, USA 3 School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, USA 10.1 Introduction With the rise in global energy demand and environmental concerns about the use of fossil fuels, the need for rapid development of alternative fuels from sustainable, non-food sources is now well acknowledged. The effective utilization of low-cost high-volume agricultural and forest biomass for the production of transporta- tion fuels and bio-based materials will play a vital role in addressing this concern [1]. The processing of lignocellulosic biomass, especially from mixed agricultural and forest sources with varying composition,

tranter shock tube tranter shock tube A shock tube for high temperature studies of chemical reaction kinetics. Overview The goal of this program is to develop a fundamental understanding of the elementary chemical reactions, non-reactive energy transfer processes, and coupled kinetics processes involved in combustion. The basic scientific approach is to combine a theoretical effort in the energetics, dynamics, and kinetics of chemical reactions with an experimental effort in thermochemistry, dynamics, and kinetics. Both the theoretical and experimental components of the program are vertically integrated to span a wide range of phenomena relevant to the study of chemical reactivity. This integrated approach produces synergy that results from the strong interaction between the theoretical and experimental efforts. Taken as a

Abstract: The subjects of contact and friction are introduced here in the context of frictionvibration interactions. The chapter begins with a brief presentation of the fundamentals of contact mechanics and friction phenomena, and continues with an examination of classic formulations and laws of contact and friction. The various steps involved in contact and friction analysis of an engineering system are outlined, and essential definitions and concepts of contact and friction are introduced. There follows a presentation of the detailed contact and friction analysis, which can be used for the analysis of general contact and friction phenomena encountered in dealing with frictionvibration interaction problems. The comprehensive treatment of interface contact and friction from macro-to micro-level are presented.

World utilization of deuterium is anticipated to increase with the rise of fusion-energy machines such as ITER and NIF. We present a new fundamental equation of state for the thermodynamic properties of fluid deuterium. Differences between thermodynamic properties of orthodeuterium, normal deuterium, and paradeuterium are described. Separate ideal-gas functions were fitted for these separable forms together with a single real-fluid residual function. The equation of state is valid from the melting line to a maximum pressure of 2000 MPa and an upper temperature limit of 600 K, corresponding to available experimental measurements. The uncertainty in predicted density is 0.5% over the valid temperature range and pressures up to 300 MPa. The uncertainties of vapor pressures and saturated liquid densities are 2% and 3%, respectively, while speed-of-sound values are accurate to within 1% in the liquid phase.